Secondary Menu Tab (local task)
I needed to add the following to my code: 

  $items['admin/settings/cvminterviews/interviewers/interviewers'] = array(
    'title' =&gt; 'Interviewers',
    'description' =&gt; 'Interviewers',
    'file' =&gt; 'cvminterviews_admin_interviewers.inc.php',
    'page callback' =&gt; 'cvminterviews_interviewers_overview_page',
    'access arguments' =&gt; array('administer cvminterviews'),
    'type' =&gt; MENU_DEFAULT_LOCAL_TASK,
  );


The important part is to make this the exact same callbacks as the 'admin/settings/cvminterviews/interviewers' menu item, but with one more level, and assign the MENU_DEFAULT_LOCAL_TASK type.