[Typo3] Menu question

[Livius Agrippa]

Hi,

I want to make a menu which shows only a part of it.
I will explain.
I have this menu
L1I1
   L2I1
   L2I2
     L3I1
L1I2
L1I3

 From the beginning the menu will look like this:
L1I1
L1I2
L1I3
When one click on L1I1 the menu expands
L1I1
   L2I1
   L2I2
L1I2
L1I3
When one click on L2I2 the menu becomes like this:
L1I1
   L2I1
   L2I2
     L3I1

The non active items on level 1 dissapear and so on (when one click one 
item on level 3 also the non active items on level 2 dissapear).

Can someone give me some ideea or a beginning point.

greetz,
Livius