policy for accessing storage media

[balazs at rainstorm.org]

Hi,

I'm using Kubuntu 7.10.
I want to set up a user policy for accessing media (cdrom, pendrive,  
memory cards etc.).
With other words I want to apply the following policy:
Only users for example in pendrive group are able to mount pendrives,
only users in cdrom group are able to mount cdroms etc.

The solution would be much nicer, if KDE's popup window only appeared  
when user with appropriate rights were logged in.
I think it can be done with suitable udev rules, but I don't know the  
exact way.
Could you give some ideas, or instuctions?
Thanks in advance!

Best regards,
Balázs Héder