In this paper we describe a Group Communication System for real-time systems and show how to use it. This System, we call Synchronized Phase System (SPS) ensures a property weaker than the classical Virtual Synchrony, but SPS, with some liveness properties is powerful enough to build Atomic Broadcast Service.
Moreover, for real-time system we can give explicit bounds on the size of good periods (periods without timing failure) to ensure the timeliness properties on message delivery.
This system has been implemented to build a Real Time Atomic Broadcast Service in the French project ATR.