Supplier Contact on PO used for the email address mergefield

When I enter a PO and specify a supplier contact, the available fields allow for a supplier contact and a supplier email; however, when I use the supplier email, it takes the default contact's email from the supplier contact list. If I choose a different contact when creating the PO, it does not pull their email, only the default for the company. It would be nice to show on the PO template that if I specify contact Y, then it will show contact Y's name and email versus how it is now where if I choose contact Y, it shows contact Y's name, but uses contact X's email since that is what the supplier is defaulted to. There is no mergefield which pulls the email of the contact used on the PO.