@boomerang,
Oh, I see.
I think it's more her general mother-hen-ness, which might be an only-child thing, I guess. But she already has a bunch of very close friends and doesn't "need" more friends, she just worries about the new kids and wants them to feel welcome. And then several of them have become good friends.
She definitely is kind of allergic to cliques, though, and is always looking outward for new interesting people. She has two very good friends who don't like each other that much, then a next level of about seven quite good friends, then a next level of maybe 25 good friends. This was more a problem in the past (when various groups wanted her to commit to them totally rather than being a member of other groups at the same time), 5th grade has been a little more porous and accepting.