Button action in attachMovie

Tried searching for this problem, didn’t find anything similar.

In my movie I attach a MC’s with attachMovie.
One of those MC’s have buttons in them.
Those buttons are supposed to trigger an action
on another MC that is also attached with attachMovie.
But it doesn’t work.
Is it impossible to trigger actions from one attached MC
to another?

b1.onRelease = function() {
    var colorful = new color("shapes");

Tried _parent.shapes, but doesn’t work.
Can somebody help me with this?