On a prior coach('92 Holiday Rambler Imperial) that was a 30 amp service, the a/c system had a selector switch for shore power. You had to select whether you wanted the front or rear unit to run. Coach was wired so that while 7500 gen set was running, the selector switch was bypassed and both units would run. You might look around for a switch of some sort that might not be labeled. Hope this helps.
"...NOT ALL WHO WANDER ARE LOST"BILBO BAGGINS
2006 FOURWINDS WINDSPORT 36Z 2012 JEEP LIBERTY TOAD