Can IDR populate the Pay Group field?

Summary:

Pay Group is a required field for our Payables invoices. We would like for this to be populated upon IDR invoice creation (or at least at invoice validation) so a user doesn't have to manually touch each invoice. We have only one BU but two Pay Groups. We do have separate Recipient email addresses that equate to the two Pay Groups but because there is only one BU, I am unable to use the Recipient Email Address Override for the BU in the IDR configurations. Is there another way for IDR to populate this or can