Composite systems are generally comprised of heterogeneous components whose specifications are developed by many development participants. The requirements of such systems are invariably elicited from multiple perspectives which overlap, complement and contradict each other. Furthermore, these requirements are generally developed and specified using multiple methods and notations respectively. It is therefore necessary to express and check the relationships between the resultant specification fragments. In this paper we deploy multiple "ViewPoints" that hold partial requirements specifications, described and developed using different representation schemes and development strategies. We discuss the notion of interViewPoint communication in the context of this ViewPoints framework, and propose a general model for ViewPoint interaction and integration. We elaborate on some of the requirements for expressing and enacting inter-ViewPoint relationships - the vehicles for consistency che...