Add emails to account/contact when EAC doesn't recognize them?

Hello!

With EAC, is there any way to allow users to manually add an email if the system doesn't sync it because there is no email to match on? Ex. an approval for pricing from a supplier that the sales user wants to have on the customer account to reference but it wasn't sent to the customer so it doesn't sync. 

I suspect the answer is no, but what have other users done to get around this?

Thank you!