Use of Approved Supplier List with catrgory

Summary:

Would like to understand the use of Approved Supplier List using Category. If we create ASL using items, we can restrict the item to be procured from a specific supplier. Is there a similar functionality for ASL using Category, if not then what is the functionality? Thanks in advance!

Content (please ensure you mask any confidential information):

Approved Supplier List is created for supplier ABC, for category MISC (No Item)

The user creates a PO for Supplier DEF using the category MISC.

The system allows the PO to be submitted for approval.

Expectation: The user is prevented from submitting the PO with a message indicating the supplier is not approved.