Several power aware routing schemes have been developed under the assumption that nodes are willing to sacrifice their power reserves in the interest of the network as a whole. But, in several applications of practical utility, nodes are organized in groups, and as a result a node is willing to sacrifice in the interest of other nodes in its group but not necessarily for nodes outside its group. Such groups arise naturally as sets of nodes associated with a single owner or task. We consider the premise that groups will share resources with other groups only if each group experiences a reduction in power consuption. When this is the case the groups may form a coalition in which they route each other's packets. We demonstrate that sharing between groups has different properties from sharing between individuals and investigate fair mutually-beneficial sharing between groups. In particular, we propose a pareto-efficient condition for group sharing based on max-min fairness called fair coalition routing. We propose distributed algorithms for computing the fair coalition routing. Using these algorithms we demonstrate that fair coalition routing allows different groups to mutually benefecially share their resources.