grub2: submenu

 
 16.1.2 submenu
 --------------
 
  -- Command: submenu TITLE ['--class=class' ...] ['--users=users']
           ['--unrestricted'] ['--hotkey=key'] ['--id=id'] { MENU ENTRIES
           ... }
      This defines a submenu.  An entry called TITLE will be added to the
      menu; when that entry is selected, a new menu will be displayed
      showing all the entries within this submenu.
 
      All options are the same as in the 'menuentry' command (See
      menuentry).