Want to Control 2 thermostats separately from one gas fired heating only furnace
You should be able to wire the thermostats in parallel.  When either one is closed, the furnace runs.

Run wires from both thermostats to the furnace.  (You likely have one set there already.)  From thermostat A the two wires (usually one black, one white, sometimes other colours) are connected to two screws on the furnace.  With thermostat B's wires connect one each to the same two screws.  So both white ones are on one screw and both others are on the other screw.

Most thermostats don't care about current direction, so one wire to each screw.

Therm A -----------------------0-------------------------------- Therm B
        -----------------------0--------------------------------
                               ^
                       Screws on Furnace