Networked enterprises create virtual teams of distributed experts belonging to different enterprises where one user can be part of multiple teams; How to effectively control the sharing of personal and shared context information among members of multiple overlapping teams without compromising their privacy is a challenging research question. This paper describes sharing control in Peer to Peer and Web service based collaborative systems. In contrast to other sharing systems which mostly use static policy and context of requester and owner, we propose DySCon, a context based Dynamic Sharing Control mechanism which allows system defined as well as owner defined runtime policy adaptation for different levels using various contexts. We evaluate our Dynamic Sharing Control architecture by implementing a prototype Dynamic Sharing Control Messenger to enhance privacy of the owner.