Adding symbols from the library without knowing there class name?

Hi guys, In AS2, i could do something like this:

[pseudocode]
for(i=0;i < array.length; i++){
clip = _root.attachMovie(array*.linkage_name, array*.new_name,nextHighestDepth);
}

In AS3:

I want to be able to dynamically loop through
var rock:BlueRock = new BlueRock();
var stone:BlueStone = new BlueStone();
etc.

any ideas?

Thanks.