OK, I bumped USC up to a Tier 1 program and dropped Notre Dame, Michigan, and Oklahoma to Tier 2. Then, I bumped 6 of the Tier 2 teams down to Tier 3, mostly on geography and rivalries. This effectively shifted most of Tier 3 to Tier 4 and Tier 4 to Tier 5 and spilling into Tier 6. Filled in the last 5 spots of Tier 6 with my best guesses - mostly from P5 ranks.

The schedule is 7 cross-group games one team from your tier from each of the other 7 groups and then 5 games against your group. OOC wins are worth one point, Group wins are worth 2 points.

Group A
1-Alabama
2-Clemson
3-Tennessee
4-Ole Miss
5-Boise St.
6-UCF*

Group B
1-Auburn
2-Florida St.
3-Penn St.
4-West Virginia
5-Louisville
6-Pittsburgh*

Group C
1-Florida
2-South Carolina
3-Miami
4-Virginia Tech
5-Missouri
6-North Carolina*

Group D
1-Georgia
2-Nebraska
3-Iowa
4-Georgia Tech
5-Texas Tech
6-Utah

Group E
1-LSU
2-Oregon
3-Texas A&M
4-Washington
5-TCU
6-Oregon St.

Group F
1-Ohio St.
2-Michigan
3-Michigan St.
4-Wisconsin
5-Oklahoma St.
6-Cincinnati*

Group G
1-USC
2-Notre Dame
3-Stanford
4-UCLA
5-BYU
6-Cal

Group H
1-Texas
2-Oklahoma
3-Arkansas
4-Kansas St.
5-Arizona St.
6-Arizona*

Top 2 from each Group advance to the 16-team CFP, with Group winner hosting the Round 1 CFP game on their home field.

Spills into the current CFP structure, with the New Year's 6 bowls, etc.

You would also set up a similar arrangement for the next 48 teams (or so) and have four relegation games among the 8 last place teams from each Group. They are replaced by the top 4 teams from the Second 48.

You would also enable up and down Tier movement, based on Group points, with OOC points as a tie breaker.