Manual Proxies and Netscape Communicator

[Green, Denise]

My library is using Windows NT and Netscape Communicator for public access
to the online catalog, periodical indexes, and other research databases via
the Web.
Has anyone figured a way to use Manual Proxies to limit access to a specific
set of URLs ? 

We only have so many computers and don't want general Web surfing at all of
them. We would like to limit access to approximately 20 URLs related to
Ovid, FirstSearch, InfoTrac, CIS Compass, UnCover, etc. Has anyone used the
Manual Proxies technique to do this?  

Any other ideas?

Thanks, Denise Green
Brookens Library