We consider a system where several providers share the same network and control the routing in disjoint sets of nodes. They provide connection toward a unique server (destination) to their customers. Our objective is to facilitate the design the available network links and their costs such that all the network providers are interested in cooperating and none of them withdraw from the coalition. More specifically, we establish the framework of a coalition game by providing an algorithm to compute the transferable coalition values. As by-product, we apply the proposed algorithm to two-player games both in networks subject to hacker attacks and in epidemic networks.