Let’s say for whatever reason the SEC is able to expand with West Virginia (such as a Pac 12-Big 12 consolidation) but no viable 16th member emerges. Missouri moves to the West. In order to deal with the unbalanced schedule caused by two divisions, several East members are allowed to count their ACC rivals as a conference game.

This is what the SEC East would see for 3 of their 9 conference games:

Florida - LSU, SEC West, Florida State
Georgia - Auburn, SEC West, Georgia Tech
Kentucky - Mississippi State, SEC West, Louisville
South Carolina - SEC West, SEC West, Clemson
Tennessee - Alabama, SEC West, SEC West
Vanderbilt - Ole Miss, SEC West, SEC West
West Virginia - SEC West, SEC West, Pittsburgh

Arkansas, Missouri, and Texas A&M would no longer have a permanent cross-division rival, but would effectively rotate South Carolina and West Virginia between them.

Each of the eight West Division teams would play two games against the SEC East and seven games against their SEC West rivals. Tennessee and Vanderbilt have no ACC rival, so their ninth conference game comes from the two leftover SEC West teams.

The drawbacks to this are that this configuration pretty much works only with 15 teams, an 8:7 split, and five non-conference rivalries. Everyone but Tennessee and Vanderbilt would need 14 years to cycle through the opposite Division home and away.

The benefits include everyone in the SEC having nine P5 opponents, maintaining the SEC-ACC rivalries, and not having to split the pie a 16th way. Tennessee and Vanderbilt would see Arkansas more frequently (10 times in 21 years), which helps build a rivalry between the neighboring states.