Invites friend to outing w/other friends, now takes over group?? Change in dynamics!?

I think your fear of losing your friends to her is making everything seem worse than what it actually is. And it is kinda weird that she doesn't introduce her other friends to you but, you can ask her to introduce you to her friends. I mean maybe it didn't really occur to her that she knows your group but you don't know hers. And of cource the dynamics changed. You have a new person in the mix which definatley makes things a little different. And about the 1up situation, just talk to her. Tell her it's kind of annoying. If youre really friends you should be able to tell each other that with no problem. When my best friend tells me I say something that hurt her, or whatever I apollogize and try to change whatever I did, cause I care about her feelings. If she's your friend she'll be understanding. Hope I helped. Best of wishes.