How can we make sure that P2P accounting inherit a specific segment of the PO?

Summary:

How to ensure that a specific segment found on a PO Expense account is defaulted in all accounting transactions of a PO from receipt to payment?

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Mapping sets are being used to derive accounts combination when Receipts , Invoices and Payments are accounted based on the source PO.

Grateful to have your advice on how to set up the system to ensure that the value of a specific segment found on a PO Expense account is defaulted in all accounting transactions of a PO from receipt to payment? The value of that segment changes based on the PO requirement and other transactions such as invoices must reflect the change of that particular segment from the PO.