There is a "to Guild" chat button in Vendetta 3.5. This might mean something, no?

How about either changing nation to Group or have an additional section called "Guild", and it could go like "The Shadows", or "Super Knights" or something like that..

So when a person targets another player, it would go:
Name: ThePlayer
Health: ----------
Distance: 4000m
Nation: Itani
Guild: Super Knights