Connecting the transformer as an auto transformer would allow one bus to be directly connected to the paralleled generators, with the autotransformer supplying the other bus. That would allow it to handle larger loads and current surges from motors, etc. on the directly connected bus.What would get rid of the problem is installing a 120->240/120 transformer. 120v from the generators and 120/240 into the panel interlock. I dont know if the little honda inverter generators would be able to magnetize the transformer before tripping on overload.
If I were installing this, I would definitely go with a dedicated subpanel for the critical loads, with a manual transfer switch between the subpanel and the main. It makes it clear which loads are on the generator, helps limit the loads, guarantees no potentially-lethal backfeed, and helps prevent someone monkeying with the set-up in the future and doing something dangerous.Substantial overloading that continuously lights the overload alarm (red) may damage the generator(s). Marginal overloading that temporarily lights the overload alarm (red) may shorten the service life of the generator(s).