To use the comparison made earlier to the NFL playoffs......... The NE Patriots beat the Steelers in the AFC Championship. So let's use that as the equivalent of a Region comp. The Patriots then went on to the Superbowl (the National game) to play against the winner of the NFC ( equivalent to the winner of another Region comp). There is no consideration of either the AFC or NFC champs having to play against another team from their conference (Region)
I realize this is going a little off course, but I'd like to fill in the NFL thing. It is
possible for teams from the two conferences to play during the regular season, and then again in the Super Bowl. I think this has actually happened. Because of how the scheduling works, in a given four year period, every NFL team will play every other NFL team at least once. An NFC team will play four games against AFC teams from a single division, and vice versa.