title: Get Different GCM registrationId for Different servers
body: <p>I am using <a href="https://developers.google.com/cloud-messaging/" rel="nofollow">GCM</a> for triggering notification to my android app. notification are triggered from my server. for example suppose the user registers an account in app then server will be sending notifications for that I am passing GCM registration id in my registration request. till now it works perfectly. now I have one more API that is another server. and I am sending the same GCM Registration Id in that request, but I am not getting any notification from that server, so from some reading I have found that each <code>registration_id</code> is associated with a particular app and its corresponding server API key i.e. a single device has different <code>registration_id</code>s for different apps Thus, we got a <em>MismatchSenderId</em> error while trying to send push notifications using the <code>registration_id</code>. how do I resolve this ? I have googled and didn't find any proper solution.</p>
  
  <p>I am generating GCM registration in this way :</p>
  
  <pre><code> String token = instanceID.getToken(defaultSenderId),
                          GoogleCloudMessaging.INSTANCE_ID_SCOPE, null);
  </code></pre>