Relays? 120 VOLT

I have led lighting in my backyard. I want to control them using ST, but when the lights are powered up, they are dark. I have to use an IR remote to set the color.

So, I started to think. I have a few extra lamp modules laying around and not being used. I have played around with the lights and discovered that they use a 4wire cable from the light controller to each led fixture. One wire carries positive 12v and each of the other 3 wire complete the circuit for Red, Blue and Green.

So, can I use the lamp unit to control a relay that then would complete the circuit directly from the LED power pack to the LEDs for the color I want.

So, I guess what I need is a relay that uses 110v ac to switch 12v DC. How would I describe this relay and find such a thing.

As long as the coil voltage is 110/120vac most any relay should work. Here is one on Amazon. I use a similar setup for my gas logs with a lamp module controlling a 120vac relay. You will just have to use multiple relays.