Little help with remote wire to two amps

I have an 18 gauge currently from the ignition switch to original amp. For second amp, I am installing distribution block for power and ground but, I'm not sure about remote wires. I know there is very little voltage needed for remote wire. Can I splice original wire and then, run a wire to each amp, run a second wire from ignition (I really don't want to do this), or consider a relay (I don't understand how a relay works)? Thanks in advance for the help.

By the way I currently have a JL 500.1 and will be adding a four channel profile to power four 6 1/2 rounds.

In general, you can use the remote on wire from most head units to switch two amps by simply jumpering one to the other.  More than two is when a relay is usually demanded.  But what is the 18 gage wire you described being used for?  I hope this is not your power supply...Support the12volt.com

No I'll be using 2 gauge wire to the dist block then (2) 4 guage wires to each amp. I'll use the same gauge wire for ground back to the battery (-)....It's for a boat application. 18 gauge wire is for the remote lead that I have wire to the ignition so amps will be on when the boat accessory is on or the boat is running.

Gotcha.  Just jump the remote on lead from one amp to the other.Support the12volt.com

Could you explain "jump the remote on lead"... Do you mean just splice the wire at some point and run two wires to each amp OR did you mean... Place a second wire into 1st amp's remote terminal running over to the 2nd amps terminal???? Thanks for your help. What would a relay accomplish?

Stock head unit with no remote wire. I replaced it with a Alpine CDA 9833 but already had an ignition remote turn on so I was going to use it. (Any wires from the HU out to the amps are down along the hull of the boat and a real pain to run) The HU is down inside the cabin.