One idea I had that is similar to this is to play each of the Theatre games (Guadalcanal, Battle of the Bulge, D-Day) and then have the winner of those sub-games gain some advantage the following Global Session, at the appropriate juncture in the game.
So if Japan wins Guadalcanal, you put Japanese units and ships there, either at game start, or later, and if the US wins, vice versa
The winner of Dday gets bonus units before/after first atl landings
b o b winner gets help defeating/protecting Germany
Only problem is these games are sorta wonky and I don’t have B.o.B.