title: Wordpress wp_list_pages: list parent page siblings
body: <p>I'm trying to get this working for quite a while now. I get close but can't find a working solution.</p>
  
  <p>My page structure is like this:</p>
  
  <pre><code>1 FIRST LEVEL
    2 SECOND LEVEL
      3 THIRD LEVEL
        4 CAR
           5 SUV
           5 MINIVAN
           5 FULLSIZE
        4 MOTORCYCLE
        4 BICYCLE
    2 SECOND LEVEL
    2 SECOND LEVEL
  1 FIRST LEVEL
  </code></pre>
  
  <p>I need a wp_list_pages statement that does the following: on 4th and 5th level pages (and ONLY on those) the navigation lists all 4th level pages. </p>
  
  <p>(When i'm on page "CAR" the navigation should be CAR,MOTORCYCLE,BICYCLE. And also when i'm on page MINIVAN the navigation should be CAR,MOTORCYCLE,BICYCLE.)</p>
  
  <p>Thank you very much for any help!</p>