Fading alpha of mc's each to a certain percent, using setInterval to delay

1

I have a movie that uses this code to load several mc’s:

var a = 1;
function attach(movieclip, x, y) {
	clearInterval(arguments.callee["Interval"+a]);
	clip = attachMovie("square","square"+1,a+1);
	clip._x = x;
	clip._y = y;
	clip.attachMovie(movieclip);
	a++;
}
attach.Interval1 = setInterval(attach, 500, "square1", -450, 25);
attach.Interval2 = setInterval(attach, 800, "square2", -410, 25);
attach.Interval3 = setInterval(attach, 1100, "square3", -370, 25);
attach.Interval4 = setInterval(attach, 1400, "square3", -330, 25);
attach.Interval5 = setInterval(attach, 1700, "square3", -290, 25);
attach.Interval6 = setInterval(attach, 2000, "square3", -250, 25);
attach.Interval7 = setInterval(attach, 2300, "square3", -210, 25);

Once they are loaded, I would like to use alpha fade on each square with progression…as in I would like to fade square1 to 80%, square2 to 70%, square3 to 60%, etc.

As of right now I am having trouble even getting square1 to fade at all, much less doing this in a progression (setInterval) with all of them.

You can view current swf if it helps envision what I am trying to accomplish.