I absolutely understand. It does help when things get ugly with one group.
I have my group in my class at my school. They’re all a year or two older than me at most (I’m young for my grade) and if I were going to, say, the movies and wanted someone to go with me, they’re the ones I’d be most likely to invite. (these days, not so much becuase they’re not happy with me.)
I have my group(s) of older theatre folks. They wouldn’t go to the mall with me, but I hang out with them at rehearsal and I’ve been invited to a few of their parties and occasionally sit with them at lunch. They intermix a bit with the ones in my class, but they mostly don’t like each other, so they never actually hang out… plus, when my friends-in-my-class are pissed at me, my older friends are more likely to be on my side.
I have my boy friends and my theatre friends from the boys’ school. They have noting at all to do with any of my other friends, other than one or two events and a couple of "oh, I work with her"s. They’re good for a break from all the estrogen.
And then, my darling lovely dance class friends. There was a boy who was in dance class with me and also did theatre, but I adored him in both settings anyway and it didn’t matter… plus he graduated and has become pretty scarce at the studio. My dance class friends range from age ten to mid-twenties and there’s no group in the world I’d rather spend time with.
Last year, my best friend from my class joined one of my dance classes. My social brain went on the fritz. I acted like a total monster to the poor girl. I went out of my way to let her know that she should not expect to be special just because I knew her. When people asked, I said “she goes to my school.” Between classes, I’d chat with my studio friends and not her. Didn’t go around and introduce her to the teachers or tell her about them or anything. (in my defense, she was being pretty annoying. Was always late and wanted me to wait for her so she wouldn’t have to walk into class alone, got mad because I was better than her and wanted me to tone it down so I didn’t “crush [her] self esteem” and was such a pain in the butt in class that none of the other girls liked her much either. Also, I was thirteen and I realize it was very childish.) She didn’t last long enough to even learn people’s names, but man that was a tense couple weeks
I’ve also noticed that my friends don’t seem to think the same way. I’ve been introduced into a number of new circles through a mutual friend… I’ve had friends take me to work with them, friends who will invite me to parties with all their elementary school buddies, friends who invite me to audition for or join their other groups (like extracurricular groups)… something which I just wouldn’t do.