This is tough. It's hard to know when to sit on the sidelines and when to jump in. If you can come up with some good questions, and a very low-key way to talk wiht the leader about what you perceive is going on, then do it. Remember when you do, that you are getting one side of the story, and it may be filtered by your daughter trying to be just like them, more than them requiring it of her. Call the leader to learn more, not to lambast her.
I was once married into a family who were very wealthy. I came from a single parent home, and we lived securely, but we didn't have any extras. This family never made me feel inferior. My "culture" was very different from theirs, but we found many areas of common ground and interests.
In addition, they didn't spend money needlessly. When I visted them, I was always amazed that some of the furniture was old and worn but not replaced. They didn't live the way I expected wealthy people to live. They didn't waste money. They invested money instead.
It sounds as if your daughter is working on becoming part of a group of girls who build their oneness by building a tight circle around each other, and counting whom they can leave out. It's hard to watch this happen, but you can't control your daughter's life, and whom she chooses to be friends.
My daughter is a freshman, and one of her friends left hte local high school to go to a private school this year. (My daughter also left, to attend a magnet school) I was talking with the other girl's mother this weekend, and she said her daughter was discovering that the kids at this private school were SO MUCH kinder than the friends she'd made in middle school. I was so pleased for her and for her mom, because this kid had chosen very snotty girls to befriend in her quest for popularity. now she's in a place where the values are different and she's finding that she can have friends with really nice kids.
I don't know how old your daughter is, but why don't you try to involve her in some other settings? My girls started ballet in middle school, which isn't the age most kids start dance, but it's given them lots of confidence and poise. The younger one added hip hop to her agenda, and doesn't even complain when every Monday she has gym class, plus 2 hours back to back of dancing. She's also getting better grades this year, even with the increased activity level.
Look for your child's interests and giftedness and try to find activities that bring those out. We can't BUILD self esteem in others. It is something they EARN by trying to do things and succeeding. I wouldn't yank her out of this group, but I would encourage her to widen her path a little. She might just find that if she gets involved in other things, swimming, fencing, karate, dance, art, whatever . . . that there are activities out there she absolutely LOVES, and that she might even find really wonderful people her own age doing them -- people who share her talent and encourage her. And THOSE are the friends you really want for your child.
We went to an "away" football game this last weekend. We were going to cheer on our band, because my daughter was in the high school marching band as an 8th grader, but the band didn't happen to come. So there we were. It was okay with the older daughter, who had friends on the home team. She left me right away. Then my younger daughter discovered she had friends there, too -- girls from her dance class. So she spent her time enjoying their company -- also on the home team sidelines. So there I sat, all alone, although I happen to enjoy football, so it was okay. I was there as chauffeur anyway. It was WONDERFUL, to realize that my girls had made friends in the course of their activities -- friends whom they could bump into and hang with when the friends they'd hoped to see weren't there. And they both had a really good time.
Your daughter will get there, too. But definately see if your budget can provide some other activities, that in the end might supplant this group's place in her life. It doesn't sound like a positive thing for her. :-)