hitTest().attachMovie() --> specified movieclip

I've got 12 movieclips (holder_mc) and another movieclip (tf_mc) to be dragged&dropped. If the drop is within one of those 12 holder_mcs, I want to be able to use attachMovie to attach the dropped clip into a specified movieclip within the relevant movieclips, movieclips, movieclip.

e.g.:

if tf_mc is dropped on to holder_mc7,  then tf_mc should be attached to holder_mc7.InnerHolder1.InnerHolder2

if tf_mc is dropped on to holder_mc3,  then tf_mc should be attached to holder_mc3.InnerHolder1.InnerHolder2

The below code is being loaded as an external swf in to _root.mc1.mc2 (hitTest is successful, but it doesn't attach as I want)

Illustrative purposes only:

var dDroppedMC:Array = new Array();

tf_mc.move.onRelease=tf_mc.move.onReleaseOutside=function(){

dDroppedMC.splice(0);

                    this._parent.stopDrag();

                    for(j=0; j<6;j++){

                                        if (this._parent.hitTest(_root["holder_mc"+j])) {

                                                  dDroppedMC.push(_root["holder_mc"+j].InnerHolder1.InnerHolder2);

                                        }

var tfP:MovieClip = mc.attachMovie("tfID","tfP"+TxtNum++, dDroppedMC.getNextHighestDepth());

///

}