Is this blur possible? - AS3

I would like to put 2 identical mc’s on top of each other… the bottom one bright red… and the top one black… and blur the one on top in such a manner that it does not let the red one be seen… (blured from it’s edge out… instead of on the middle)

Is that possible? like specifying where the blur should start (like how you can specify in some programs if the border is in the middle, exterior, or interior of a box)