Maybe you can create a group with 2 “dummy” items:
Group gWetterstation "Wetterstation" (gFF) [ "Thermostat" ]
Number WetterstationCurrentTemp "Wetterstation IstTemperatur [%.1f °C]" (gWetterstation) [ "CurrentTemperature" ] { knx="0/3/0" }
Number WetterstationTargetTemperature "Wetterstation Dummy SollTemperatur" (gWetterstation) [ "TargetTemperature" ]
String WetterstationHeatingCoolingMode "Wetterstation Dummy Heating/Cooling Mode" (gWetterstation) [ "homekit:HeatingCoolingMode" ]
Then ask Alexa: “Alexa wie ist die Temperatur von “Wetterstation”?”
EDIT: You will see this “OH2 item group” as only one device in Alexa-APP: → named “Wetterstation” ! You can link it also to an Alexa-APP group, e.g. “Wohnzimmer”. Then just ask: "Alexa wie ist die Temperatur von “Wohnzimmer”?