Masks over Masks?

hy everyone,

i got 1 movieclip, in that movieclip i got 1 image in 1 layer… and in other layer i got one matrix of squares… so then when i mask the image i only get only the images by squares. I got u understand what i mean for this…

But now im trying to had a motion so that some squares shine over the time. i dont have any ideia how can i make this…

i hope u guys can help me!!