Why wouldn't this work?
Brew beers - Pale Ales, IPAs, Stouts
Carb each to appropriate levels 2.2 - 2.8 for the pale ales and IPAs, 1.2 - 1.7 for the stout
Use beer gas (70 - 30) in the kegerator for all beers, lower pressure through normal faucets for the Pales and IPAs, higher pressure for...