Fix cross faction interaction

--HG--
branch : trunk

src/game/GroupHandler.cpp

@@ -215,6 +215,8 @@ void WorldSession::HandleGroupAcceptOpcode( WorldPacket & /*recv_data*/ )
     uint8 subgroup = group->GetMemberGroup(GetPlayer()->GetGUID());
 
     GetPlayer()->SetGroup(group, subgroup);
+
+    group->BroadcastGroupUpdate();
 }
 
 void WorldSession::HandleGroupDeclineOpcode( WorldPacket & /*recv_data*/ )