Whhooo. I had no idea you were planing on working multiple zone valves off one thermostat. If you actually believe that you could have one area that will represent an acceptable average of the whole house temperature, then there is an easier way to try to do what you want if you only have a one pump system.
Leave your chosen thermostat that is in that average house temperature spot conected as is. Just maually push the operating levers on the other zone valves to the fully open position. Most zone valves have a diagonal slot at the end which can hold the zone valve lever from returning to the closed position. Now you only need to disconect one thermostat lead from the thermostats you don't want working and voila! Whenever your chosen thermostat calls for heat, it will be going out through all the other zones.
If you end up not liking your one thermostat/ 5 zone ideal, it will take two minutes to reverse it the way it was.