Multiple instances of mask Movie Clip?


this is what I want to do but I’m not sure how to go about it:

I have a series of photos that I to open on top of each other. Each new photo opens from the center of the previous, moving out in a widening circle. I’ve made a mask that works with two photos, but I haven’t figured out how to add a third, and to add another instance of the mask. Once a fourth photo loads, the first can be discarded, the other two are moving out in concentric rings. When the fifth loads, the first is gone. it won’t be seen again. The second disappears when the fifth appears, and so on.

I hope this isn’t too confusing, and that someone has an idea how I could accomplish this. Thanks!