title: Send emails (using Postfix) from two different domains
body: <p>I have two Ruby on Rails applications, and two virtual domains (mydomain1.com and mydomain2.com)(using Apache+REE+mod_rails).
  I use Postfix as mail server.</p>
  
  <p>So I have myhostname = mail.mydomain1.com in main.cf
  And that's because why the sender is always mail.mydomain1.com, no matter from which application I send emails.</p>
  
  <p>I need all emails sent from application on virtual domain mydomain1.com have Received: from mydomain1.com, and from second Rails app on mydomain2.com — Received: from mydomain2.com</p>
  
  <p>Is that possible? </p>
  
  <p>Thanks!</p>