Interference is one of the most challenging issues in wireless network. Communication between a transmitter and receiver pair causes radio wave propagation to interfere with other nearby communication that may result blocking that link. In Multicast, since almost simultaneous communication takes place along several branches of a Multicast distribution tree, these branches tend to mutually block each other due to interference. In this research we introduced an Interference-Aware Multicast routing protocol. First, it divides the nodes in the Multicast distribution tree in three GORby-Groups: Transmit, REC1 (receiving) and REC2 (standby). Then we calculate the SINR of the node based on interferences caused by all the nodes within that GORby-Group, assuming when the given node is in the transmit mode then all the nodes within its GORby-Group will also be in the transmit mode. Then we use the computed SINRs in our join Multicast group algorithm to achieve the most SINR.