Which means it's possible for all three teams to be undefeated.
I know there's a lot of football still to be played, but that's the downside of scheduling without divisions - an undefeated team left out of the conference championship game.
It's hard to imagine such a team being left out of the playoffs (not being ranked in the top ~10.
Divisions has its own downsides. In a division with round robin play it's possible to have a three way tie - but at least all teams that are tied down are not undefeated.