How do I display submenus separately from their menu tree? I'm trying to display all 3rd level submenus for a menu item on one page, with each in its own display block. I've tried the Menu Block module but it only seems to work for the active trail, which means I can only display all 2nd Level and 3rd Level menus as one unit rather than just 3rd level menus as separate units.

In addition to the Menu Block module, I also tried access the menu tree directly with this code.

      $main = menu_navigation_links('main-menu', '2');
      echo theme('links__system_main_menu', array(
      'links' =&gt; $main,
      'attributes' =&gt; array(
      'id' =&gt; 'main-menu',
      'class' =&gt; array('links')
    ),
  ));
?&gt;


Here's the menu structure:

- Parent Menu 1
- Parent Menu 2
  - Child Menu A
    - SubChild Menu 1A
    - SubChild Menu 2A
    - SubChild Menu 3A    
- Child Menu B
  - SubChild Menu 1B
  - SubChild Menu 2B
  - SubChild Menu 3B


What I'd like to display when Parent Menu 2 is selected:

Block 1:    SubChild Menu 1A  | Subchild Menu 2A  | SubChild Menu 3A

Block 2:    SubChild Menu 1B  | Subchild Menu 2B  | SubChild Menu 3B    

Any help on the right way to display submenus separate from their tree would be greatly appreciated.
I think the best way to go about it is to just use the Menu block module. Here is a quote about it (from the module's project page):

... have you ever used the Main and Secondary menu links feature on your theme and wondered “how the hell do I display any menu items deeper than that?”
Well, that’s what this module does. It provides configurable blocks of menu trees starting with any level of any menu. And more!
So if you’re only using your theme’s Main menu links feature, you can add and configure a “Main menu (levels 2+)” block. That block would appear once you were on one of the Main menu’s pages and would show the menu tree for the 2nd level (and deeper) of your Main menu and would expand as you traversed down the tree. You can also limit the depth of the menu’s tree (e.g. “Main menu (levels 2-3)”) and/or expand all the child sub-menus (e.g. “Main menu (expanded levels 2+)”).