[BobCratchett]

Forgive me if this question has already been asked and/or has been answered.
I have a main video library and a subset of it that only contains 3D movies.
If I create a favorites and add that favorites in the menu that works fine.

But I need to keep track of the # of 3D movies, watched 3D movies , unwatched 3D movies, and recently added 3D movies.
How do I add those as sub menu items?
It also would be nice if I can reference the 3D favorites in terms of 3D movies statistics also.

I really would appreciate if I can be pointed to a tutorial on how to do that.

In addition to the playlists solution proposed by Mike, you can also use video nodes (wiki) to split up your library. With that option, you can use the Skin Shortcuts: Add To Menu content menu add-on (see my signature) to add the node, along with the sub-nodes as submenu items, to your main menu. (With the context menu add-on installed, go to 'Videos', highlight your new node, bring up the context menu, select 'Add to menu', choose 'Main Menu' as the target, then whatever subnode you want as the default view for the main menu item. The library node editor tries to make it easy to manage your library nodes within the Kodi GUI.