Reduce new tickets being created when responding to an email/using the email request type function.

Current Issues Scenario: When someone submits a ticket via the "email" request type, it creates a new ticket. Now, if others are CC'd on the note and they begin to add additional information responding to the request, it creates a new ticket every single time. 

Suggestion: Are there quickparts or some text that can be added to the subject line, so that when anyone replies or sends and email with, for example (ticket #1234) in the subject line, the reply and new information is added to the ticket, rather then generating a new ticket that needs to be merged?