Disable Morph-drag in a PasteUpMorph

Hi guys,

again, I have to ask a rather interesting question. Say, you have a  
PasteUpMorph, inside which you have put other elements, maybe other  
morphs, or images, or something like this. I would like the contents  
inside to be fixed, meaning that you should not be able to pick up a  
morph inside the PasteUpMorph and move it around.

Can you guys let me know if this is possible?

Cheers,
Marcus