In Req-to-PO Automatic Substitution, can you system substitute an item that uses a different Vendor?

In Req-to-PO Automatic Substitution, can you system substitute an item that uses a different vendor? Going from Original item from Vendor 1 on an ePro Req, Auto-Source runs, get a PO with Substitute Item from Vendor 2. (We have a highly automated system where the ePro Req is generated automatically, approved & sourced before being interacted with by a person)