Regulating an existing thermostat/boiler based on TRV temperature sensor

I have a thermostat which I can configure through IFTTT. I’m able to set the temperature and the mode. The mode consists of three schedules which I can configure on the thermostat itself and a manual mode.

Alongside this I have a few Tado TRV’s connected to some radiators in my house. I want to set up a schedule in Home Assistant which only turns on certain radiators during certain times of the day.

What I have in mind now is to check the TRV’s temperature sensor, and say if I want that room to be 20 °C, I send this as a manual setpoint to the thermostat, which then turns on the boiler. However, the thermostat will regulate itself based on its own internal temperature sensor.

How do I go about this? I’m concerned about seriously messing up the efficiency of my boiler if I’m always sending setpoints back and forth.