Product Function in Pivot Tables from Multiple Consolidation Range
 

I've created a pivot table off of data from two other pivot tables. One
pivot table has $millions by product by quarter, and the other pivot table
has volumes by product by category. The first table only has some products,
but the second one has every product. When I create a pivot table with
multiple ranges referencing these two tables and have the values multiply, if
there's no entry in the first table it assumes 1 instead of 0 and returns the
total volume. Is there any way around this, or some other tool in Excel that
would accomplish what I want? Any suggestions would be greatly appreciated.

Thank you!