Indication rule that checks if subfields are in the same field
Currently it is not possible to write an indication rule which checks the subfield a and b of a field only when both subfields are in the same field and not in repeated fields of the same record. Both of the following records are treated the same when looking for a subfield a "mercury" and subfield b "venus" in the 690 field:
690 $$a mercury $$b venus
690 $$a mercury $$b mars
690 $$a earth $$b venus
I'd appreciate an option to distinguish if I'm looking for subfields in different fields or in the same field. We need this quite often for our local fields, as our data reflects different classifications via subfield 2.