Member Filter: Summation of an Expansion

Hello,

Is there a way to aggregate the result of an expansion within a member filter?  For example, I have multiple entities that are Australian.  I would like to aggregate the balances of all of those entities into a single row.  I'm using the attached syntax which produces the entire list, but I would like all the results to be aggregated into one line item without all the underlying detail.  Does anyone know of a solution?

Thanks,

Sean