How can I associated a second contact's email correspondence to a deal?

How can I associated a second contact's email correspondence to a deal?

Hello, 
I created a deal and added a contact and began corresponding with that contact. Email correspondence around the deal is appearing as expected in the deal's email view. Recently I've begun corresponding with a second contact about the same deal. I've added the second contact via the contacts roles view. Email correspondence to the second contact about the deal is not appearing in the deal's email view. I searched help and browsed through the deal and contact module, but I cannot figure out how to tell Zoho CRM to associate certain emails from the second contact to the deal. How do I do that? 
Regards, 
Carl