Assigning Purchasing Categories / Ship-To Locations To Buyers

Hello,

I was wondering if there is a way to assign a buyer more than one Purchasing Category or Ship-To location during the Buyers setup? Client distributes their buyer workload Department / Agency. However, during the Buyer setup, you can only assign one Purchasing category / Ship-to location.  There should be some way to assign a Buyer more than one Category / Ship-To. 

See attached screen capture display duplicate entry error when I  try to enter additional assignments to the buyer.

Thanks,

Anthony