Sure, you could come up with a heavy current relay and arrange a switch to energize the relay. That’s the purpose of a relay, to use a low current circuit to enable a high current circuit.

The first thing that came to mind was an old Ford starter relay. The problem is that the Chinese ones are all that are available today and the quality of them is horrid. It could be that you could find one from the general aviation world. If it is one that is TSO’d, meaning that it is certified for use in certified aircraft it would be stupid expensive. Many items though are available for experimental aircraft that are the same but no paperwork, thus much cheaper. Determine how much current it needs to handle and browse the Chief Aircraft website. They are a good supplier for aircraft electrical items. If that one doesn’t work try Aircraft Spruce.

Yes, the starter relays are for intermittent use, but the aircraft relay is for continuous use supplying main power and supplies current all the time when in use.

Hope this helps.