Generators
I'll tell you what I did. If you search some of the other RV websites you can find numerous posts on this issue as well as photos. Some hookups are fairly elaborate, my setup is not so elaborate but is very functional.
I purchased a 30 amp female cord end from camping world. I used two 3' pieces of 12 ga 3 conductor wire, installed polarized plugs on the end of each piece of wire. Some have bought the short ready made cords with preinstalled polarized plugs and a 3 outlet receptacle that they cut off and discard. I then hooked the wires together and connected them to the female 30amp plug. The 12 ga wire with outer insulation wouldn't fit so I had to strip it and use electrical tape.
remember white wire to silver screw, black wires to the gold screws and green wires to the green screws or ground screw.
Install one plug in each generator and then start them one at a time.
Important to remember that if either plug is removed from a generator while the other is running that it will be HOT!
Confused? If so search on some of the other sites, 2 users with useful posts are named NH_Bob and Pulltoy.
Good luck.