[Typo3] menu - list: special.value in 3rd navigation level possible?

[Detlev Wagner]

Hi list,

My top-navigation is a tmenu layer drop-down menu. 
In this menu I want to show in the third level only distinct main items
(like special.value = ...).

I don't know how to realise  this "special value list" for my 3rd navigation
level.

-"excludeID" isn't possible because some BE-Users create their pages in the
third level .

-"hide in menu" isn't possible, because my left navigation is a classic
expand list and has to show all items.

Thanks for answering this newbie question!
- Detlev Wagner (wagner-d)