Ecliped by transparency

i have 2 Movieclips each of them has a bitmap and a sprite in there center of that bitmap
-the sprite has a MouseEvent
-the bitmap undates on enterframe
(some of the bitmap transparent. that is why i’m using a small area(sprite) for clicking,the reason there is so much transparency is for uniformed sizing of the images being using)

when the Movieclip’s bitmap is in close proximity of a second movieclip the sprite is visible threw the transparancy of the first bitmap the second sprite unable to recognize MouseEvents,

i would like for the mouse to ignore the bitmap
unfortunately i cannot add {.mouseenabled = false} to the bitmap

thank you for any suggestions