Centaur Clans and Tribes
Centaurs are very clannish when it comes to relating to others, even within their own species. Most interactions between clans are in the form of skirmishes and battles.
If two centaurs see each other on the plains, they have special flags to identify one another by tribe or clan. If not of the same tribe the two centaurs will generally avoid one another unless they wish to trade.
Centaur clans are large, while tribes are small.