I'm in a tight spot...
One of my bridesmaids is my groom-to-be's twin sister. We met a year before I met her twin, about 9 years ago and were very close throughout high school and into college. However, while we were once close, we had a pretty rough falling out about a year and a half ago. Despite that, and though he and her are not close, my fiance wanted her in the wedding, as my brothers and sister are in our WP. I was fine with that; I didn't argue or care... until...
She takes every open opportunity to try to embarrass me, make hateful statements, or cause a rift between a member of her family and I. It is to the point where at our engagement party, his mother didn't say a word to me. She (the twin sister) has to maintain a specialized diet because of a medical condition, and I made accomodations for her and she made comments like, "Oh that's what you got? I prefer XYZ." "You know I can eat plain old XYZ." When we went dress shopping, all of my BM's came with me. She sat in a chair and frowned. She made one comment about the one dress that I said - before I tried it on - that I didn't like -- she said it was her favorite. She told her mom that I was very rude about her opinion. If I say anything to my fiance, he gets upset, because he is very close to his parents and they are very protective of his sister. (Yes, it is all this petty!)
At one point, she was friends with almost all of my bridesmaids (most of us went to highschool together.) In fact, she was "best friends" with one for 10 years, but she blew everyone off. They have tried to "play nice", but they are growing tired of her attitude as well. It's sad, and sometimes I feel bad for her. Most of the time, however, I'm just pissed and don't want her in the WP. I don't want to discuss it with my BM's because I don't want to "add fuel to the fire", so to speak.
I'm just looking for advice? It's a particularly tough situation, because after the wedding, she will not be my fiance's sister -- she'll be my sister-in-law. Help??