onEnterFrame in a for() lopp

Hey I have this code to go through all my movieclips and give EACH of them an onEnterFrame function.

for (var i = 0; i<menuTot; i++) {
var thumb:MovieClip = holdThumb.attachMovie("thumb", "thumb"+i,holdThumb.getNextHighestDepth());
thumb.onEnterFrame = function() {

So the problem is that the only onEnterFrame function that works is the last movieclip. Obviously there is somthing wrong when defining it as it is only taking the last thumb variable for the name. How do I get it so each thumb clip gets its own onEnterFrame function?
Thanks for your help