multiple thermostat /how to associate a Smart Radiator Thermostat to defined Thermostat

Dhhh

Hello ,

Here is my installation :

-Thermostat 1 (room1 ) linked to Boiler 1

-Thermostat 2 (Room2 )linker to Boiler 2

-I have 1 bridge

All my existing Smart Radiator Thermostat are connected to Thermostat 1,

I just purchased a new Smart Radiator Thermostat that I would like to link to the Thermostat 2 but in a different room (room3)

I have tried but this operaton is impossible because my new Smart Radiator Thermostat always wants to be connected to Thermostat 1 .

Does someone know how to associate a Smart Radiator Thermostat to defined Thermostat ?

Thanks you for your help.