I am installing a outdoor wood furnace and I also have a heat pump I need to make it so my thermostat works as follows. my primary source of heat will be the wood furnace for this to provide heat to the house the thermostat only need to turn on the fan. Say we leave and the fire goes out then I want the heat pump to take over and provide heat to the house. The ac will work as it does now. I would like to avoid using 2 thermostats due to the fact that they would both use the same blower and that produces another problem from what i have been told.