Can I control floor heating room and boiler with same thermostat?

I have some radiator thermostats upstairs. Downstairs I have 4 rooms with floor heating. All 4 rooms have a wired thermostat. The one in the living room I now have as main thermostat to control the boiler. But now I cannot control the floor heating in the living room. I created a schema of how I have/want it. But I'm strugling with the livingroom.

I'm afraid I need separate thermostats for each floor heating room and an additional device as main thermostat, Is this correct? If so, what device do I need? If not, how should I connect the wires?