Shore Power Question for the Sparkies

[dieselguy]

This question is about taping off the 15 amp circuit in many 30 amp campground power pedestals to run a second 13500 BTU A/C. Yes, I'm aware that some 30 amp pedestals available wiring may not support tapping off the 15 amp plug.

I'm looking at adding a 15 amp Marinco plug in in the side of a fiver and running that separate line to a stand alone 15 amp receptacle in the storage bay near the A/C power line to the front air conditioner. That OEM A/C line will be interrupted by male and female 20 amp plugs so I can plug it in to the stand alone 15 amp receptacle when the need arises. With the fiver thermostat controlling both A/C's ... do you think there will be an issue with 2 separate inlet power feeds off the campground power pedestal as far as damaging the thermostat's common control to both A/C's?

Thanks in advance