diff --git a/api/postal.proto b/api/postal.proto
index 644fa6f..25aed7e 100644
--- a/api/postal.proto
+++ b/api/postal.proto
@@ -11,6 +11,7 @@ enum DeliverResult {
 service Postal {
   rpc Deliver(ReqDeliver) returns (ResDeliver);
   rpc DeliverBatch(ReqDeliverBatch) returns(ResDeliver);
+  // broadcast request to postal cluster
   rpc DeliverGroup(ReqDeliverGroup) returns(ResDeliver);
 
   // rpc GroupCreate(ReqGroupCreate) returns(ResGroupCreate);
@@ -67,12 +68,12 @@ message ResGroupCreate {
 
 message ReqGroupJoin {
   string uid = 1;
-  repeated string gid = 2;
+  repeated string gids = 2;
 }
 
 message ReqGroupLeave {
   string uid = 1;
-  repeated string gid = 2;
+  repeated string gids = 2;
 }
 
 message ReqGroupDissolve {
diff --git a/pkg/protocol/deliver/deliver.go b/pkg/protocol/deliver/deliver.go
index 09e1ab1..b72597c 100644
--- a/pkg/protocol/deliver/deliver.go
+++ b/pkg/protocol/deliver/deliver.go
@@ -34,7 +34,7 @@ func NewDeliver(msgInServiceName string) *Deliver {
 	}
 }
 
-func (d *Deliver) InitWithResolver(ctx context.Context, resolver discovery.GrpcResolver) (err error) {
+func (d *Deliver) InitWithResolver(ctx context.Context, resolver discovery.GrpcResolver, opts ...grpc.DialOption) (err error) {
 	balancer.InitConsistentHashBuilder()
 	rb, err := resolver.Resolver()
 	if err != nil {
@@ -42,12 +42,13 @@ func (d *Deliver) InitWithResolver(ctx context.Context, resolver discovery.GrpcR
 	}
 
 	postalUrl := resolver.DialUrl(postal.Postal_ServiceDesc.ServiceName)
-	conn, err := grpc.DialContext(ctx, postalUrl,
-		grpc.WithTransportCredentials(insecure.NewCredentials()),
-		// consistent hash lb
-		grpc.WithDefaultServiceConfig(fmt.Sprintf(`{"loadBalancingPolicy":"%s"}`, balancer.ConsistentHash)),
-		grpc.WithResolvers(rb),
-	)
+	var options []grpc.DialOption
+	// consistent hash lb
+	options = append(options, grpc.WithDefaultServiceConfig(fmt.Sprintf(`{"loadBalancingPolicy":"%s"}`, balancer.ConsistentHash)))
+	options = append(options, grpc.WithResolvers(rb))
+	options = append(options, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	options = append(options, opts...)
+	conn, err := grpc.DialContext(ctx, postalUrl, options...)
 	if err != nil {
 		return
 	}
@@ -55,9 +56,12 @@ func (d *Deliver) InitWithResolver(ctx context.Context, resolver discovery.GrpcR
 	return
 }
 
-func (d *Deliver) InitWithAddr(postalAddr string) (err error) {
+func (d *Deliver) InitWithAddr(postalAddr string, opts ...grpc.DialOption) (err error) {
 	// Conn *grpc.ClientConn
-	conn, err := grpc.Dial(postalAddr, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	var options []grpc.DialOption
+	options = append(options, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	options = append(options, opts...)
+	conn, err := grpc.Dial(postalAddr, options...)
 	if err != nil {
 		return
 	}
diff --git a/pkg/protocol/deliver/group_deliver.go b/pkg/protocol/deliver/deliver_group.go
similarity index 62%
rename from pkg/protocol/deliver/group_deliver.go
rename to pkg/protocol/deliver/deliver_group.go
index 053b25b..b8d5399 100644
--- a/pkg/protocol/deliver/group_deliver.go
+++ b/pkg/protocol/deliver/deliver_group.go
@@ -2,9 +2,12 @@ package deliver
 
 import (
 	"context"
+	"fmt"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/credentials/insecure"
 	"google.golang.org/protobuf/proto"
 	"sonet/api/gen/postal"
+	"sonet/pkg/grpc/balancer"
 	"sonet/pkg/grpc/discovery"
 	"sonet/pkg/utils/logger"
 	"sync"
@@ -14,15 +17,11 @@ type GroupLoader interface {
 	Load(uid string) (groupIds []string)
 }
 
-type Postal struct {
-	conn   *grpc.ClientConn
-	Client postal.PostalClient
-}
-
 type GroupDeliver struct {
 	svcName           string
 	groupLoader       GroupLoader
 	resolver          discovery.Resolver
+	postal            postal.PostalClient // postal consistent hash client
 	postalDialOptions []grpc.DialOption
 	postals           map[string]*Postal
 	lock              *sync.RWMutex
@@ -42,8 +41,13 @@ func NewGroupDeliver(
 	}
 }
 
-func (d *GroupDeliver) Init(ctx context.Context) (err error) {
-	// initial all postal clients
+func (d *GroupDeliver) Init(ctx context.Context, grpcResolver discovery.GrpcResolver, opts ...grpc.DialOption) (err error) {
+	err = d.initPostal(ctx, grpcResolver, opts...)
+	if err != nil {
+		return
+	}
+
+	// initial all postal direct clients
 	servers, err := d.resolver.ResolveAll(ctx, postal.Postal_ServiceDesc.ServiceName)
 	if err != nil {
 		return
@@ -58,6 +62,28 @@ func (d *GroupDeliver) Init(ctx context.Context) (err error) {
 	return
 }
 
+func (d *GroupDeliver) initPostal(ctx context.Context, resolver discovery.GrpcResolver, opts ...grpc.DialOption) (err error) {
+	balancer.InitConsistentHashBuilder()
+	rb, err := resolver.Resolver()
+	if err != nil {
+		return
+	}
+
+	postalUrl := resolver.DialUrl(postal.Postal_ServiceDesc.ServiceName)
+	var options []grpc.DialOption
+	// consistent hash lb
+	options = append(options, grpc.WithDefaultServiceConfig(fmt.Sprintf(`{"loadBalancingPolicy":"%s"}`, balancer.ConsistentHash)))
+	options = append(options, grpc.WithResolvers(rb))
+	options = append(options, grpc.WithTransportCredentials(insecure.NewCredentials()))
+	options = append(options, opts...)
+	conn, err := grpc.DialContext(ctx, postalUrl, options...)
+	if err != nil {
+		return
+	}
+	d.postal = postal.NewPostalClient(conn)
+	return
+}
+
 // watchPostal watch postal service list
 func (d *GroupDeliver) watchPostal(ctx context.Context) (err error) {
 	ch, err := d.resolver.Watch(ctx, postal.Postal_ServiceDesc.ServiceName)
@@ -90,10 +116,7 @@ func (d *GroupDeliver) buildPostals(servers []discovery.Server) {
 			logger.Errorf("dial postal server %+v error: %v", server.Addr, err)
 			continue
 		}
-		postals[server.Addr] = &Postal{
-			conn:   conn,
-			Client: postal.NewPostalClient(conn),
-		}
+		postals[server.Addr] = NewPostal(conn)
 	}
 
 	// close old connection
@@ -101,9 +124,7 @@ func (d *GroupDeliver) buildPostals(servers []discovery.Server) {
 	d.postals = postals
 	for addr, p := range oldPostals {
 		if _, ok := d.postals[addr]; !ok {
-			if err := p.conn.Close(); err != nil {
-				logger.Errorf("close old postal conn %s error: %v", addr, err)
-			}
+			p.Close()
 		}
 	}
 }
@@ -114,20 +135,21 @@ func (d *GroupDeliver) DeliverGroup(ctx context.Context, gid string, msg proto.M
 	if err != nil {
 		return
 	}
-	req := &postal.ReqDeliverGroup{
+	req := postal.ReqDeliverGroup{
 		Gid: gid,
 		Msg: message,
 	}
 	for _, p := range d.postals {
-		res, err := p.Client.DeliverGroup(ctx, req)
-		if err != nil || !res.Ok {
-			logger.Errorf("deliver to postal failed: %+v, %v", res, err)
-		}
+		p.DeliverGroup(&req)
 	}
 	return
 }
 
-func (d *GroupDeliver) GroupJoin(ctx context.Context, uid string, gid []string) (err error) {
-
+func (d *GroupDeliver) GroupJoin(ctx context.Context, uid string, gids []string) (err error) {
+	req := &postal.ReqGroupJoin{
+		Uid:  uid,
+		Gids: gids,
+	}
+	_, err = d.postal.GroupJoin(ctx, req)
 	return
 }
diff --git a/pkg/protocol/deliver/group_loader.go b/pkg/protocol/deliver/group_loader.go
deleted file mode 100644
index 9eae15d..0000000
--- a/pkg/protocol/deliver/group_loader.go
+++ /dev/null
@@ -1 +0,0 @@
-package deliver
diff --git a/pkg/protocol/deliver/postal.go b/pkg/protocol/deliver/postal.go
new file mode 100644
index 0000000..05f4993
--- /dev/null
+++ b/pkg/protocol/deliver/postal.go
@@ -0,0 +1,35 @@
+package deliver
+
+import (
+	"context"
+	"google.golang.org/grpc"
+	"sonet/api/gen/postal"
+	"sonet/pkg/utils/logger"
+)
+
+type Postal struct {
+	conn   *grpc.ClientConn
+	client postal.PostalClient
+}
+
+func NewPostal(conn *grpc.ClientConn) *Postal {
+	return &Postal{
+		conn:   conn,
+		client: postal.NewPostalClient(conn),
+	}
+}
+
+func (p *Postal) Close() {
+	err := p.conn.Close()
+	if err != nil {
+		logger.Error("postal close error: ", err)
+	}
+}
+
+func (p *Postal) DeliverGroup(req *postal.ReqDeliverGroup) {
+	// todo put in chan
+	res, err := p.client.DeliverGroup(context.Background(), req)
+	if err != nil || !res.Ok {
+		logger.Errorf("deliver to postal failed: %+v, %v", res, err)
+	}
+}