Multi-User Coordinated Multi-Point (MU-CoMP) transmission mode is considered as one of the key technologies which offer a good quality of service to low capacity users while maintaining a high spectral efficiency in the system. However, MU-CoMP networks have to determine the total number of users supported by CoMP operation as well as the size of the SDMA (Spatial Division Multiple Access) users' groups permanently. Previous studies often considered static selection criterion and bandwidth reservation for CoMP transmission mode. In this paper, we deal with dynamic CoMP transmission mode selection jointly with bandwidth allocation problem in order to meet the system performance requirements. We propose a new scheme which takes into account the variation of users' quality of service and the total load in the cluster. Significant improvements are obtained in both total system throughput and outage probability in the cluster with our proposed scheme.