Coalition

A coalition is an alliance among entities (Stakeholders), during which they cooperate in joint action (semi-collective action), each in their own self-interest. This alliance may be temporary or a matter of convenience. A coalition thus differs from a more formal covenant.

http://en.wikipedia.org/wiki/Coalition

Coalitions can be studied as games (Game Theory, Games Theory). The Nash Equilibrium defines conditions where rational players can benefit other players in the coalition.

cf Political Network