Align the B1G with 20.
I know there are 6 schools that will NOT want to be joined with the PAC 4.
https://btaa.org/
If the Big Ten was forced to split into divisions, I kinda like the idea of splitting the Big Ten into 3 separate 6-team divisions
North
Wisc, Minn, Iowa, Minn, Wash, Ore
South
USC, UCLA, ILL, NW, Ind, Pur
East
Penn St, Ohio St, MD, Rut, Mich, Mich St
Play every team in your division every year (5 games a year)
Play 12 teams in other divisions once every 3 years (4 games a year)
Then tweak it so that USC and UCLA play Wash and Ore more often and play Minn, Neb, Iowa and Wisc less often.
Also tweak it so that Wash and Ore play ILL, NW, Ind and Purdue less often and play USC and UCLA more often.
As a result it would also be tweaked so that Iowa, Neb, Minn, Wisc would play ILL, NW, Ind, Purdue more often.