How to stop Windows Explorer from examining Zip files?

Windows Explorer apparently does some sortof examination of zip files when browsing to give you tooltip information like number of files in the zip, etc.  This is causing problems over slower WAN links, making network browsing really slow, and sometimes even giving people "file in use" errors when trying to delete/move files because someone else happens to have the same folder open in Explorer.  The file isn't really in use by anyone, it's just that someone else has the same folder open in Explorer and Windows is constantly scanning the zip files.  I'm sure that normally this happens really quickly, but over a VPN connection or slow WAN link it takes a second or two for each zip file.

I've been searching but have had no luck in finding a way to turn this off.  Is there a registry hack or something to disable this feature?  I need to disable this on all our Vista and XP machines.

Thanks Experts!