How to present two filters when one depend on the other?

I have two filters in a filter bar that are like supplier and product number. Each supplier has a list of products. Some products might have the same product number. Right now I have a typeahead for supplier to filter by supplier, and a typeahead for product number to filter by product. However, it seems confusing because one kind of imply certain values of the other. How is this type of relationship usually presented?