Before anyone says she is banging other dudes, we are in a large social group consisting of 15 or so members. We usually hang out together but tonight the girl (I'll call her T) hung out with 4 (one girl and 3 guys) members of the group at a block party. Frankly, I'm not emotionally invested in T and I'm really using her as a doorway into this social group, but I would still like to keep her on the hook.

We have kissed prior, and I know T is interested in me (haven't had the chance to hang out alone and take things further yet though)

Anyways, 2 of the guys T was with pose no threat (for a multitude of reasons) but the third one may be (the reason for this post) I would say we are equal SMV (he may be a little higher) but I haven't seen him in this group setting so I haven't established myself as dominant over him yet.

I'm not really concerned with anything happening between them (definitely don't have oneitis for this girl) I just want to know how to proceed from here. I guess it's an insult that i wasn't invited to this party...?

I feel my reputation is on the line of T gets with M.

Do I go no contact with T? (Hard next is not an option until I'm more established in this group)

Should I just ignore it and try to determine what happened/ if anything?

Work to undermine M from the group?( feels extreme )

Please save the rants about people telling me to get over this girl, I'm just here for advice on how to proceed. Thanks guys