Groups, such as nations, religions, organizations, or sports teams, are rarely homogeneous. Almost always they are internally differentiated, latently or explicitly, in multiple ways. For example, an organization can embrace different professions, ethnicities, genders, sexual orientations, and specific and generic roles. There is an intrinsic tension between the overarching group and the multiple ways in which its members can be categorized. The resolution of this tension hinges on many factors, among which is the extent to which the group feels under threat.