It's not going to work this way.
In the unsubscribe link, you will need to pass the email as a URL parameter:
<a href="http://mydomain.com/unsubscripe.php?email=johndoe@company.com">Unsubscribe</a>
most hosts require that the from address be a valid email address for your domain but you can set the return Address to use a dynamic value.
Open the bindings panel, click the plus button and select URL variable, set the URL Variable name to email, and use that binding for the return address setting.