This paper presents a concept for the composition of tracking systems in the context of Virtual and Augmented Reality (VR/AR) applications. Several independent 6 DOF tracking systems can be used simultaneously to accomplish the interaction requirements for a given application. The control unit for tracking systems, processing measurements with optional properties as time stamps and quality values is described as well as procedures for the coordinate system alignment of different tracking systems and the configuration of such a hybrid system. Considerations on the way accuracy errors might increase or decrease by combining tracking systems are included. The concept is motivated considering a medical AR system combining optical and electromagnetic tracking technology as example