PO20 Item Adds - Force Validation against Item master

When Requisition Items are Added as Special/Service, there is a setting within RQC_config.xml that allows for special_item_validation to be set to skip, warn, or deny. Is there a similar setting for PO Line creation? Or, has anyone customized PO20 so that it will do this type of validation before adding a new line? I was presented with this issue by purchasing and couldn't find anything on the PO side that was as easy as the RQC setting . . . Thanks