This is where, if you are going to be with this group your, SO is going to have to step in and let them know that you belong to him. If not, human behavior in groups will dictate that they will try to use you or try to dom your dom. Personaly, it sounds like a crowd you should not be hanging around with, it appears to create unecessary stress for your relationship, but I am very particular about who I am around and intolorent of rude behavior. Your description has undertones of more trauma than what you leting your SO know about. If this is true then you need to let him know, if he cares about you he will not expose you to that stress. If he still wants to expose you to the stress to satisfy his curiosities, then you know his character.