I have a dual convection oven, and an overhead commercial exhaust fan that I’d like to automatically turn on any time either oven it turned on. I can’t just connect both ovens to the fan or anytime one is turned on the other will be fed power back thru. Should I use a relay in each oven. The relay would isolate the power. So the relay in each oven would be 120vac on the coil, when the oven is switched on, and the relay load would be 120vac to the exhaust fan. So either oven switched on would only feed power back to the load side of the other relay, and not affect the oven itself. This sounds like a good option, unless someone sees a flaw in it, or something better? Thanks.