As similar folks have written in, I have emails from sources other than the customer email address that need to be recorded in the stream of activities for that customer.

Specifically, when a payment comes in from PayPal, the email address that the payment is "from" is a Paypal address.

I would like to reassign this email to the customer, whose email address appears later in the email, so that I can see the entire list of touch points with that customer, including when he/she pays the bills!

:)

This is quite common in offline CRM desktop programs.