I don't know how exactly it would be the better, but I has this idea to get some kind of statistics on duels between members of clubs AAAA and BBBB: something like "AAAA 14 - 11 BBBB".

Whenever a duel between two members of these groups happen, the counter would increase at the end of the match.

Maybe a way for clubs to configure a specific "opponent" to display on their profile page?