Post Processor Tweak for Laser Change Z to C

I'm looking for ways for the post processor to substitute the Z height to the C axis which I have as my laser intensity.

My laser intensity is read from C0 to C1 (Zero to Full power) my logic is that if the post processor can change "Z" to "C" when it outputs I can control laser intensity by varying my tool path depth.

I looked into the post processor logic but I don't think there is a way to add your own variables (limited to the ones listed in the manual table), am I correct?