When sending an email from an order, the "To" field automatically defaults to the customer's email when sending the email from the communications tab.  Is it possible to default to another email address after selecting a specific email template?

During the order process, a document gets emailed to the transportation company.  The email for the transportation company is stored on the opportunity record.  Is it possible to set the email template to pull this field into the "To" field on the email screen instead of the customer email address?  I don't see a place to specify a "To" field on the email template.

Any assistance would be greatly appreciated.  Thank you!