Yeah, not quite there yet. A large part of it is that I am pretty new to MDX.

Pseudo code would be:

for every member of product

divide x by y

only if product.category = 2

then roll this up to an aggregate

The aggregate needs to be able to be sliced from the top of the dimension down to the different hierarchies in the dimension.

I know it's not much, but that's the best way I can describe it 🙁