I have the living room area heating covered by two means: underfloor heating pump controlled by BDR91 and somewhere next to the stairs going to a basement, I have a radiator controlled by an HR92. There is an Honeywell T87RF used as temperature sensor for the room and associated to the UFH zone.

I cannot for the life of me make both the UFH and radiator to listen to the T87RF as one zone. At the moment they are 2 separate zones setup but not ideal, as there is 0.5 to 1C difference between where the T87RF and HR92 sit. Tried all combinations possible, multiroom, etc, it appears that this combination if heating one zone one room not possible?

Anyone having similar setup maybe have different ideas?