I currently have a gas furnace. I want to remove the gas furnace and replace my system with a 13 SEER heat pump with 2-stage gas furnace as 2nd/3rd stage heat. My problem is that I have a 3 zone Trol A Temp system in my house which makes it very diffucult for the wiring. How the heck do I lock the heat pump out at 40 degrees. I cant use the new touchpad T-stats because I don't have enough wires at all 3 thermostats right now. Too diffucult to pull new T-stat wires and too expensive to replace all thermostats. What is out there that will do the job on a multizone system.