title: Google Admin SDK - add group to another group using Java client API
body: <p>I can add a member to a Google Group like this:</p>
  
  <pre><code>directory.members().insert(&lt;groupKey&gt;, &lt;member&gt;).execute()
  </code></pre>
  
  <p>If I want to add a <em>group</em> to the group instead of a <code>member</code>, how do I do it? I can retrieve a Group reference like this:</p>
  
  <pre><code>Group myGroup = directory.groups().get(myGroupKey).execute();
  </code></pre>
  
  <p>... so how do I add it to a specified group?</p>