I have a sailboat with two 3k 120v Multiplus inverter/ chargers that are currently set up to provide split phase. They work just fine as set up now while on shore power or generator but I would like to stack them parallel to increase the available wattage while inverting. I am wondering if I can leave the AC input wired as if split phase but wire the output as if they are parallel to give me what I am looking for while inverting. The concern that I have is both the shore power and generator are 50amp and have L1 and L2 hot wires (220v) and the multiplus inverters do not have an input for L2. I put together what I think is a schematic that will work but would like to get thoughts before I rewire the inverters. Please don't look too much into the illustration for the ground, it is not complete. I also could be completely off base on this and what I am trying to do is not possible, so please let me know if I am. If this is not possible as depicted, would adding an isolation transformer be my next best step?