My fiancee and I want to keep our wedding party small. So far I've only asked my sister and college roommate to be my bridesmaids (my sister is the MOH), and he's asked his 2 best friends to be groomsmen. The problem is, my fiancee also has two sisters and a brother. His brother is in Afghanistan and may not be back in time for the wedding, so my fiancee isn't asking him to be a groomsman. But I feel that I should still ask his sisters to be bridesmaids, even though I'm not close with either of them. I know he doesn't want me to because he and his older sister don't get along (and I can't ask one and not the other). It's his family and I don't want to interfere, but I also don't want them to feel like I'm slighting them. What should I do to maintain good relationships between everyone?