In this paper, we propose an interference-aware multicast routing scheme for a single-radio Wireless Mesh Networks carrying multiple multicast flows. We focus on multicast routing over WMNs with stationary nodes, such as community wireless networks. We present a new metric that is based on three components: Path Interference Cost (Ip), Broadcast Benefit Factor (BF), and Hop Count (HC). We proposed a formula to compute Link Interference Cost that is aggregated into Ip. The goal of our metric is to choose a join path to multicast tree for a new receiver node that causes lower intra-flow and inter-flow interferences. The benefit of the proposed metric is to improve flow throughput. We also proposed a route discovery scheme for discovering the join path, computing metric, and making route selection. We evaluated the performance of our scheme through simulation under variety of network conditions.