How to disable a particular list item in flash cs3

Friends,

I need a small help on list component in flash cs3.

assume that i have 5 items in my list and i want to disable 3,4,5 items from mylist box. how to do this ??

item 1 – enabled state
item 2 – enabled state
item 3 – disabled state
item 4 – disabled state
item 5 – disabled state

using flash cs3, i want to achieve this , how to do this ?? any ideas pls…

Rajesh