Is there a way to show the PO comms email on the req creation page instead of the contact?

Summary: Is there any way for the req contact field on req creation page to pull from the supplier site purchasing tab - choose email - then email ID here instead of contact? The field we use on purchasing tab is what we'd like to review and that is what automatically pulls into the PO so why would it be pulling from the contacts on req page and not the supplier site communication method email that is ultimately where the PO will be routed if nothing is selected on req creation page.

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