title: Assign rules to sub account in Mandrill
body: <p>I have a project with an single API key in Mandrill. It has three sub-accounts: production, staging, development. I have created a rule that rejects all requests that don't match a small list of domains and I want to apply that rule to both the staging and development sub accounts. The idea is to not accidentally spam clients while we are testing.</p>
  
  <p>I don't see how I can apply the rule to different sub accounts. Is it possible? If not, and I need to create different APIs for each environment, can someone explain when to use sub-account vs when to create different API keys.</p>
  
  <p>As a bonus, when an email matches a rule, is it possible to reroute it to a specified address instead of rejecting it?</p>