title: WordPress | Adding a custom post menu under custom menu in the admin
body: <p>I am trying to create a plugin, with a Dashboard page, config page, some extra pages for configuration and some custom post types.</p>
  
  <p>More specific, in the admin I like to have some pages added in the menu via the functions <strong>add_menu_page</strong> and <strong>add_submenu_page</strong>, as well I like to create some custom post types related to the plugin.</p>
  
  <p>The question is, how to group the custom post types menus under the plugin menu options.</p>
  
  <p>In example, lets say I creating the menu option "MyPlugin" with the function <strong>add_menu_page</strong> and then below this menu I adding the pages "Settings Page", "Do stuff page", "Dashboard" via the function <strong>add_submenu_page</strong> and then I create the custom post type "Cars". How can I place the "Cars" menu under the MyPlugin menu option ?</p>
  
  <p>The final result I like to be like that :</p>
  
  <pre><code>Dashboard
      Home
      ...
  Posts
      All Posts
      ...
  Settings
      General
      ...
      ...
  MyPlugin             &lt;- How to add this menu structure ?
      Dashboard        &lt;- How to add this menu structure ?
      Cars             &lt;- How to add this menu structure ?
      Settings Page    &lt;- How to add this menu structure ?
      Do stuff page    &lt;- How to add this menu structure ?
  </code></pre>
  
  <p>The actual issue is not how to create the menu structure, but how to add the "Cars" custom post type menu under the MyPlugin menu.</p>
  
  <p>Note I have try the following option in the "register_post_type" attributes with no luck</p>
  
  <pre><code>'show_in_menu'          =&gt;  'admin.php?page=myplugin.php'
  </code></pre>
  
  <p>Is that posible to achived ?</p>