Social division with endogenous hierarchy

Many societies are divided into multiple smaller groups. Certain kinds of interaction are more likely to take place within a group than across groups. I model a reputation effect that enforces these divisions. People who are observed to interact with members of different groups are believed to be less trustworthy by members of their own group. A hierarchical relationship between groups appears endogenously in equilibrium. The information requirements for my equilibrium to exist are much less demanding than the information requirements in related models. These different information requirements correspond to concrete differences between the institutions of different Indian castes