Add field/column to incident queue report

Content

We have email links on our individual websites related to specific products.  Customers use these email links to ask questions about that specific product. The emailed questions drop into an incident queue.  I need a field/column on our incident queue report that shows which website email address the sender used for the emailed question. (I'm not looking for the individual senders gmail address, as we know how to add that.) Can anyone offer advice?  Thanks in advance.

Version

November 2015