simple, add ND to Atlantic, Navy to Coastal. Switch Pitt to Atlantic and Syracuse to Coastal. Each school plays at least 8 conference games, all in own Division and 1 cross rival (ND-Navy). Division rep in championship determined by records against own division only. Head to Head decides ties.
This way, ND could continue playing it's annual rivals (USC, Michigan, Michigan St, Purdue and Navy). They would also play other long time rivals every year (BC and Pitt have each played ND 9 times over the last ll seasons).
All schools would be encouraged to schedule other ACC schools during their 4 open dates, but would not have to.
Navy, for example would continue playing Army and AF every year, and could schedule Maryland and Rutgers (both traditional rivals).
Potential Clemson Schedule: wk1: Furman (warmup, support instate school) wk2: UGA wk3: WF wk4: Notre Dame wk5: Pitt wk6: GT (cross rival) wk7: Maryland wk8: BC wk9: NCST wk10: FSU wk11: UNC (optional conf game) wk12: South Carolina