In the ABA we have modified round robins the last day of a tournament. The teams are broken down to Flight A, Flight B and Flight C. We play half of the matches before lunch and the other half immediately after lunch.
It's definitely important to know when you're able to schedule off to play your home regional (or any national within shouting distance). It's also important not to alienate anybody. Twice at Washington I had a delightful time playing in 2 side games for 8 gold points!