how to create a virtual device from a long MQTT message

[DeRubenS]

Hello,

i want to make 1 or more different virtual devices from a long MQTT message.
the whole message looks like :

{"Sensor Data Qty":4,"INV compressor Qty":1,"STD compressor Qty":0,"Fan Data Qty":1,"Low noise control":"OFF","Outdoor air temp.(R1T)":15.5,"Pressure":0,"Voltage (N-phase) (V)":190,"DHW setpoint":45,"LW setpoint (main)":30,"Leaving water temp. before BUH (R1T)":28.7,"Leaving water temp. after BUH (R2T)":28.2,"Inlet water temp.(R4T)":27.4,"DHW tank temp. (R5T)":41.9,"Circulation pump operation":"OFF","Flow sensor (l/min)":0,"Water pressure":1.8,"BE_COP":0,"M5VIN":"4.96V","M5AmpIn":"104.375mA","M5BatV":"4.15V","M5BatCur":"0mA","M5BatPwr":"0mW","WifiRSSI":"-58dBm"}

for example i want tu make an VD for only the Leaving water temp.
could someone help me with this ?

With kind regards.