Hello Nisse!
Eve Thermo measures the temperature way too close to the valve, so it is not really important. Because the offset is a value that we can only set in Eve and HomeKit does not even know about it, To set the ofsset the best was is to set a desired target temperature like 22 degree then measure with a thermometer in the middle of the room. If for example 19,5 degrees is reached, the offset would be -2,5 degrees. Please forget about the temperature measured by Eve Thermo.
Eve does not support groups as we know from Home (yet), sorry. Eve only support groups for using with Siri.
I'll pass the request on to the developers.
Best regards and stay safe! Volker
Apr 25, 2020