MDX Crossjoin filtering on different hierarchies from the same dimension is very slow
I found an answer here that has helped my situation and now the query returns very quickly. It appears the HAVING clause is a better solution than using the Filter function as long as the dataset is reasonably small. However, I noticed that removing NON EMPTY from the second axis (ON ROWS) causes it to still be slow even using the HAVING clause. I may still need to resolve that problem, too. But, at least the first problem is solved.