David,
Sorry if I was not clear...yes, I saw the part about running it as a separate system of dedicated outlets with out ANY connection to other AC outlets (which would require a separate additional transfer switch to allow these dedicated outlets of the added inverter to be active when on shore power.)
I was specifically replying in my post above to the notion/question of possibly using a passive transformer for 'summing' the output of #1 and #2 inverters as 72chevy4x4 described it. My rambling answer was why it was not likely without specially built equipment...and a simple transformer was not the means to that end.
As always, if GS would publish the schematics for our coaches (even generic ones if they do not want to commit to disclosing variations per coach VIN number...) we could discuss these questions in a more detailed and helpful way. That Prevost coach my prior company had Vantare' build out had complete CAD drawings of all the AC wiring, the DC wiring and fiber optic cabling that was installed, along with about three file drawers of other documentation... I have nothing like that for my Tour Master T-40C
Chuck