Abstract: Complicated control and management functionality is required in a CSCW supporting environment which supports multiple collaborations running simultaneously. Synchronous interaction with multimedia real time group communications is another key issue in the high performance CSCW supporting environments. This paper presents a new model of CSCW supporting environment. The model separates the management and control aspects of collaborations and resources, and uses the OSI manager/agent model to enhance the management functionality. In addition, multi party multimedia communications related issues such as call/connection control, multimedia real time transmission, and resource management are considered in the model. Also described are the design and implementation of a CSCW supporting environment prototype system in ATM network and Unix operating system platform.