Should my brother be a groomsman if I'm in his wedding?

I have 3 sisters, and we we're all in my brother's wedding as bridesmaids. We've all been in my sister's wedding, as well as my brother. We've known the bride for a very long time, so she was able to accept us being in the party quite easily, which forced her to choose two of her friends as maids of honor. Her brothers and cousin are my brother's groomsmen, as well as my sister's husband, and two of his buddies are his best men. My boyfriend and I have discussed what we will do for our wedding, and this came across as a big issue. I want my brother in my wedding, supporting me. He doesn't really know my brother that well, and hasn't really had the chance to get to know him. He has a lot of good buddies that he'd like as his groomsmen- but some more than others. If he had the chance to get to know my brother (since we're not even engaged yet) would it be considered ok for me to expect him to allow my brother as his groomsmen? What would you do?