Consider a MIMO interfering broadcast channel (multi-cellular network) where each base station transmits signals to the users in its own cell. The basic problem is to design linear transmit/receive beamformers that can maximize the system throughput in the presence of both inter and intra cell interference. To ensure user fairness in the system, we consider the joint user grouping, power allocation and beamformer design problem by maximizing a system utility which aims to strike a suitable trade-off between the user fairness and system throughput. We propose a simple algorithm to solve this nonconcave utility maximization problem and establish its convergence. The simulation results show that the proposed algorithm significantly outperforms the SVD-MMSE method and some other approaches in terms of system throughput while respecting user fairness. The proposed algorithm exhibits fast convergence and is amenable to distributed implementation with limited information exchange.