Currently when a new contact sends a question to our support email and it doesn't match a contact in CRM / Desk, a new contact is created.

Ex: John Smith sends a question to our helpdesk through his personal email rather than his work email. Since his personal email does not match any contact in our CRM or Desk, a new contact gets created in Desk. 

Is there a way that I can catch this email before a contact is created in Desk, reassign it to the contact we have in Desk / CRM, and then continue to create a ticket in his name?