When using the Top N operator on the detail section, any group totals
continue to display the totals for the entire set.

For example, if I want to see the top 5 products for each department
by sales, and I have a group on department, I want the totals to
reflect just those top 5 products for each department, but the totals
reflect all products.

We put a query in to MS, and they said this was by design.

Does anybody have a workaround for this?