Distributed multimedia systems must handle multiple continuous media streams at once. The network subsystem must thus be able to transmit aggregation of VBR streams effectively. Data smoothing and shaping is necessary for high quality transmission. Flexibility is also required to handle different types of data formats and contents. In this paper, we propose the VoR system, a network subsystem framework for VBR continuous media transmission. It controls stream multiplexing by the scheduler in the network driver along with the QoS coordinator middleware. The system provides a way for application programs to interact with the underlying network. The system is designed on the principle of policy and mechanism separation, which enables to flexibly adapt to application dependent inter- and intra-stream QoS tradeoffs. Our preliminary result using MPEG2 streams indicates that while simple multiplexing gains some bandwidth utilization, better multiplexing can be achieved by providing more elaborate data dependent policies.