What kind of relay do I need?

I want to install LED strobe lights in the rear of my truck that will also double as a replacement for my reverse lights.

I have a on/off toggle switch that's in my truck that I want to use to activate the strobe feature, then I want the lights to come on solid automatically when the truck is put into reverse.

The lights are turned on solid, and are controlled by a Whelen controller. This control has 2 inputs. One input requires 12V+ to activate, and the other input requires two 12V+ to activate.

So I was figuring that I could set up the first input (that requires 1 12V+ signal) to be solid (reverse lights), then the second input (that requires 2 12V+ inputs) to be the flash pattern.

To do this, I'll need a relay that can be activated by the reverse lights, and that'll send one 12V+ signal to the controller... then it will also accept a second 12V+ signal that I'll split from the on/off switch and have one wire go to the relay and another go to the 2nd 12V+ signal on the controller.

But, I'll need these two inputs to be completely separate - I don't want the 2nd 12V+ input to backfeed into the reverse light system and screw up the truck.

So basically I need a relay that allows for two separate 12V+ inputs that won't feed into eachother, and either one of the 12V+ relays will allow the relay to put out one (or two) 12V+ sources.

Anyone know of where I can find a relay to do this? And what a part # would be for a relay capable of this?