c99,
The only company that I have experience with that had an inverter that would successfully survive conflict was TRACE. They warned against it, but old dummy me managed a dozen or more connections. The inverter shrugged it off.
You know you do not HAVE to utilize your rigs transfer switch or risk the transfer switch inside the inverter. Make your own diverter using a relay and a touch button wall timer. I just purchased a 2-5-10-30 min 1-2-4 hour switch that fits a duplex box. Has nifty LED pilot lights beside each button. 1,825 watt capacity.