For communication networks in distributed real-time environments, it is required that the delivery time of individual message meet the timing constraints and the average transfer delay for all messages be minimized. These special real-time requirements are usually not satisfied by the existing network protocols. This paper presents a communication architecture and a dynamic control protocol for real-time communication in multiple token ring networks. The network can be formed by multiple channels through bandwidth subdivision of a high speed ring. A flexible preemption and dynamic load allocation scheme is developed which can reduce the lost percentage of critical packets and maintain a high channel utilization at the same time. This performance improvement is demonstrated with extensive simulation results.