In this paper, a clustered network on chip (C-NOC) a modified model of Hermes NOC (H-NOC) is introduced. The clustered NOC switch has four local ports. When the packets are switched to local ports, the network traffic load and, consequently, the average delay time of a packet are decreased in group communication. When the distance of nodes in each group are increased in a mesh, the performance of mesh is decreased in group communication. But the performance of clustered NOC is increased for at least 19.7%. In clustered NOC, when the size of network is decreased, the average delay time and the total clock pulses are increased. These results indicate the clustered NOC is a suitable candidate for group communication.