Assign bidder to product category - what does this do?

Hi,

we are running SRM 7.0205, and using the bidding engine.

in the business partner master data, there is a "bidder data" tab and has an area to add product categories to a bidder.  What does this do?  If I assign product categories to a bidder, does this mean they can only respond to RFx line items with these product categories?

cheers,