I was told that since my group is larger than 10 ppl, if we wanted to eat together we would have to go to the buffet at Cassava Terrace.
Well that's a drag : ( Is that the official answer from Couples? Have you talked to the wedding coordinator? Does that go for both lunch and dinnertime?
You'd think that if you made reservations for a large party ahead of time, then most of the specialty restaurants would be able to plan for and accommodate you and your group. Especially if you guys offered to eat at off-peak times.
Another idea is to make reservations for 2 parties of 6 people at the same place/time, and hope you sit near each other. I've also heard of people paying to do private dinners for their weddings, but no idea what the cost would be.
Finally, I've yet to visit Couples but I don't think eating at the Terrace is the end of the world... I totally understand that you'd want to go to a fancier place, but the Terrace might be more fun in the sense that people will be getting up for seconds, moving around the table, and it's easier to pull up chairs to talk with each other without bothering other guests as mush, etc. Try to think of the silver lining.
Either way, congrats on your wedding and I hope you have a great trip.