Well we did get this sorted out and thank you to each of you that took time to respond. I went back and forth many times on whether to say something or just hope for the best. And luckily things kind of just came together.
My mom had actually planned on calling my aunt on something completely different and basically let my aunt do some talking about wedding details and the issues they are having (apparently BTB is somewhat disorganized). My mom just asked who she is sitting with and aunt said she couldnt remember everyone but that my brother & I were definitely at the table

However

apparently my uncle in the background overheard the conversation and spoke up. Apparently my father had said something already. My aunt then asked my mom if she thought they should put us at different tables!

Yippee...problem solved and it didn't necessarily come from me!
I was absolutely totally completely prepared to just deal with it. I had thought about it and if we were seated together I would just live thru it and walk away if any drama happened. Luckily I can relax a little and enjoy the time with the rest of my family.
Oh ya..Suzannen your wedding sounds like this family wedding!! My parents are not married (15 years divorced) and yes they are both invited to this wedding. It is actually my dad's side of the family but my mother is still very much involved. In fact this same family had a wedding for a different son about 7 or 8 years ago and talk about DRAMA! My father and 4 of his brothers all got divorced within a few years of each other but they all had been married more than 20 years. My cousins felt, and still do, that these women had been their aunts for 20 years and the divorces did not change that so every one of them was invited. There was over 400 people at that wedding reception and they did a very good job at keeping all the ex's on seperate ends of the room. It was actually one of the best weddings & receptions I have ever been to (except my own

) Good Luck on your planning and keep me posted!