How to Associate multiple contacts with deal in Sales Inbox

How to Associate multiple contacts with deal in Sales Inbox

Hello,

I have many deals that have multiple potential customers associated with a single deal, for example an engineer and a manager. The manager is the Deal's primary contact in CRM and the Engineer is added to the deal in the "Contact Roles" Associated List.

They will both send me emails regarding the same deal, but in SalesInbox the Manager will show up under the Deals column but the Engineer will only show up in the "Contacts & Leads" column. How can I get them both to show up in the Deals column?