Poser File Organizer from D3D http://www.renderosity.com/mod/bcs/index.php?ViewProduct=62459&vendor=288865 can do this completely.

With P3DO I didn't try this up to now. So I'm not sure if it is dereferencing fully to delete content.

But in each case you have to be very careful in doing deletion by program's. They normally are not informed about other content using the same ressources, e.g. texture maps. I would suggest better to use a move operation and to have the no longer needed content for a time in a "quarantine" befor deleting at all. So if you miss some resource you can rearrange them. Better than searching in zip's for new installation.