Item Category Mapping for Punchout

We are in 12.1.3  and implementing Iprocurement with Direct Punchout to Supplier. All the Supplies from a Single Supplier is mapped with Single  Item Category. In the Set up  - Ecommerce Gateway  , mapping has to be done with Buyer's Category ( Internal Value )  with the External 1. Now in our case   Internal Value will remain same   ever ( Say MISC.MISC)  and External 1 value will change. In case if supplier is having   say 100 Catalogs, then is there 100 entries to be done in the  Item Category mapping.

Thanks in advance for your help.

Jagan