Is it possible to derive the Tax Classification Code from an Item Categorie in Purchasing?

 I know that it is possible to build a rule in eTax to derive the Tax Classification Code based on an Item when you enter a requisition via Inventory Based Product Classifications.But is it also possible to build a rule in eTax to derive the Tax Classification Code on a Requisition/PO if there is no Item used but only the Item Category is available?

Example is a NON-Catalog Requisition/PO.

Any help is welcome here. We're on version R12.1.3.

Regards Menno