The multicast routing is very important for Mobile Ad hoc Networks (MANET). Though many multicast routing protocol are proposed, we consider ODMRP, which is a mesh based routing protocol. In ODMRP the reliability of the communication can be maintained by putting the relay nodes in the mesh. However, when the network is overloaded the performance of ODMRP is deteriorated. In this research, we try to reduce the number of relay nodes. We use the round robin scheduling for the route construction of many sources. The performance evaluation via simulation showed that the proposed method has a high packet delivery ratio and low communication delay compared with ODMRP.