Use the Group EDI Identifier as Extended Criteria for Proce

We are looking into expanding our WebMethods EDI use and we have run into an issue with processing rules and similar document types.
Since the EDI document type is not editable, we cannot add GS Id as an Extended Critera as we could if it were an XML document. Group ID is not a choice for Extended Criteria, group type is.
Seems like such a common issue since the GS Id was created for application distinction for document types.

For example, if we have a process to handle 997s from our trading partner’s ASN and a separate process to handle the 997 for an Invoice, do we have to create a service to call each independent process based on the same processing rule? Seems like it would get pretty unwieldy if we added all our message types. Does anyone have a comment?