They’re a clique that’s all that is. Men are cliquey. Gossip circles.
There’s probably some unspoken entry thing that they’re not even aware of. “what’s the passphrase?” but with lots of passphrases.
and if you observe carefully, I suspect members of the clique are “in” and “out” at any given time. Backstabbing, subgroups, “Hey lets not invite Jacob this time, just us” type stuff – is probably common.