Using OR() in CUBEVALUE()
Solution 1:
Okay, so I have found an answer for this, so for anyone else who faces this challenge, formula format below:
CUBEVALUE("ThisWorkbookDataModel","measure","month","filter1",CUBESET("ThisWorkbookDataModel","filterA","filterB","filterC"))
Where filter1 is a 'constant' filter, and filters A,B, and C are variations of a filter within a given field. Using the CUBESET seems to replicate the OR required.