So I'm having trouble with my bridal party....FH has two sisters. Sister A, I love. We share interests, clicked almost immediately and have spent lots of time together, even though we live several hours apart. Sister B, on the other hand, is the opposite. We *should* share interests, but she's very stubborn, inflexible and out-right rude at times. She has asked my FH multiple times (including after we were engaged!) when he was breaking up with me. At Sister A's wedding, A asked B if she would be her MOH and B declined. Sister B didn't even want to go to the wedding (their mother forced her, so says FH).
So my question is this: If I ask Sister A, am I obligated to ask sister B? Is it rude, improper, stepping-on-toes if I don't? I don't want her up there with me, but she's also going to be in my life for the rest of my life (along with the rest of the family) and I don't want to make things tense. What are your thoughts?