Validation to check for GRN (PO Receipt) at invoice level

Summary:

Validation to check for GRN (PO Receipt) at invoice level

Content (required):

We have invoice matching process, where we will match invoices with Purchase order and below are the options defaulted on PO schedule.

Inovice match option - Order

Match Approval Level - 3 way

Also we have invoices submitted by suppliers from the supplier portal. Whenever we receive an invoice from supplier portal, we need to add validation to check if GRN (PO Receipt) is available for PO or not before invoice validation is done. Please let us know what are the options available to add validation at the invoice level.