Controlling MC highlite via different Buttons

Hello all, Pls Help and greatly appreciate your feedbacks

I am trying to make ThumbNail Highlite via button and MC.

Each of the Thumbnails has a same button with instance named “item” 1 to 40.
Also, I have the highlite MC instance named “highlite” 1 to 40 as well

I am able to triggar the “highlite” MC with the following:

onClipEvent (enterFrame) {
_root.main_nav_mov.item1.onRelease = function() {

But I can not figure out how to deactiveate it when I click onto the other thubmnail buttons.

So, in general, I can active the highlite, but can not deactivate it

I have tried the following within the “highlite” mc action but it doesn’t seem to work:

onClipEvent (enterFrame) {
_root.main_nav_mov.item1.onReleaseOutside = function() {

many thnx