Every team would play every other team in their division. There would be two free game slots to play other P8 teams on the last two weekends of the season (rivalries).
Then the champions of each conference would face off based on relative rank: 1-8, 2-7, etc. The winner of the tournament would be the P8 champion,
You could have similar divisions for the G6 teams (I'm not bored enough to make those conferences, maybe sometime later). There could be a facsimile tournament for them. And you could have a "Super Bowl" at the end of the season where the P8 and G8 champions faced off. That would quell the monopoly rumors and, if the P8 champions are worthy, it should be a cakewalk against the G8 champ.
Hell, you could have a P8/G8 combined tournament if you wanted, but again, I'm not bored enough to make G8 confeveres. Maybe you could even have the G8 teams in a separate division of those conferences and add a conference title game where the winner gets the playoff spot so the G8 fans and teams can quit whining about not getting a fair shot. I tried to make them 8 teams each, but a few may have more or less.
It makes too much sense, so of course the FBS PTBs wouldn't allow it to happen.
Below are the conferences I made a few years ago. I may have already posted it here. The state abbreviations were to help me organize by region.
Spoiler:
I may have missed a couple teams. Please let me know if I did.
