Drag and drop

How do i stop the other pieces when I have draged and doped this one, its a puzzle 

p1.addEventListener(MouseEvent.MOUSE_DOWN, fl_ClickToDrag_24);

function fl_ClickToDrag_24(event:MouseEvent):void
{
p1.startDrag();
}

stage.addEventListener(MouseEvent.MOUSE_UP, fl_ReleaseToDrop_24);

function fl_ReleaseToDrop_24(event:MouseEvent):void
{
p1.stopDrag();


if(tar1.hitTestObject(p1.hit1))

p1.x=205.2;

p1.y=254.8;}