Get array of clips visible under a mask

Hello All,

hopefully ive got someone here may have already solved my problem …

im masking an array of clips to create a content slider.

My question is how can i get an array of visible movieclips.

My reasons for this is im wanting to show the numbers to and from the user is able to view and and if the user scrolls the masked clip and its cuts half a thumnail off then id want it to snap to the nearest edge so its flush against the side of the mask.

Anybody got an ideas?

Thanks