drag div from inside div to inside another

[123Jim]

Hi all,
########example HTML:##########
<div id="holder1" class="draggable">
<div id="mover" class="draggable">moveme</div
</div>

</div id="holder2" class="draggable"></div>
##########################

Is it possible to drag <div id="mover"> from <div id="holder1"> in to
<div id="holder2"> so that the 'mover' becomes attached to the 'holder'

In the above structure I can drag 'holder1' and 'mover' will stick to it,
that's fine, but when I drag 'mover' to 'holder2', it still gets dragged
around by 'holder1', just outside of it.