Maybe the "regional opponents" mirror the football divisions?
To a certain extent they probably will, but it can't be exact. It is also complicated by the fact that the eight schools without an in-state rival need more regional rivals than the six schools with an in-state rival.
Ie:
Per the Conference website, in a six year cycle each team will play:
- In-State rivals 12 times (twice each year, no exceptions)
- Regional opponents 10 times (twice each year for four years and once each for two years)
- All other teams nine times (twice three years and once three years)
Running the math:
- In a six year cycle each team needs 120 opponents
The six teams WITH in-state rivals will play:
- Their in-state rival 12 times
- That leaves 108 slots to fill with the other 12 teams where x*10+(12-x)*9=108
- When you solve that equation, x=0 so the teams WITH an in-state rival have NO regional rivals
Thus, teams WITH an in-state rival will get to 120 games in six years as follows:
- 12 games against their in-state rival
- 108 games against the other 12 teams (9*12=108)
- 120 total games
The eight teams WITHOUT in-state rivals will play:
- The other 13 teams where x*10+(13-x)*9=120
- When you solve that equation, x=3 so the teams WITHOUT an in-state rival will each have three "regional" rivals
Thus, teams WITHOUT an in-state rival will get to 120 games in six years as follows:
- 30 games against their three regional rivals (3*10)
- 90 games against the other 10 teams in the conference (10*9)
- 120 total games
This also means that the teams WITH in-state rivals will not be regional rivals of ANY school.
This would effectively force Ohio State's regional rivals to be the three Eastern schools (PSU, RU, UMD). Four of the five teams in adjacent states (M, MSU, IU, PU) already have in-state rivals and are thus exempt. The other one is Penn State. Additionally, other than the Eastern schools the next closest (geographically) to Columbus are the two Illinois schools but they obviously already have in-state rivals as well.
Therefore, I assume that the eight teams without in-state rivals would be grouped into a Western group of UNL, UW, MN, and IA and an Eastern group of RU, UMD, PSU, and tOSU.