Define a calculation field or a text field with an auto-entered calculation: door No Field & ", " & Street Address Field & ", " & PostCode Field
Substitute ( List ( door no; street address; post code ) ; ¶ ; ", " )
on your layout set up the three as merge fields in a text object:
<<door no. field>>, <<street address field>>, <<Post code field>>
(it should contain data from 3 fields, than I can use for look up lists
That might be problematic to do as small variations in how the address is entered (avenue instead of street, for example) could keep a given address from looking up the correct data.