I don't know why it has to be geographical, but the East is stacked for both football and basketball. I think the intent is to have a balance spread of teams in each division. I don't know if geography will play in the splitting of divisions.
A: UM, OSU, MSU, Minn, Wisc, NW
B: Neb, PSU, Ind, ILL, Iowa, Pur
Just a thought, but I don't know if there is a perfect solution.