Ignore reload for some time ?

Hi,

I am running Squid1.2beta24 as an accelerator for Apche with an attached
Database System. What I'm trying to do is to avoid a DoS-Attack by Users
pressing Reload too often and so producing too much work for the
Database System (which is generating the HTML-Pages dynamically).
How can I achieve this ?
It would be nice to configure Squid to return only the cached Object
for, say, 1 Minute before checking/retrieving the page (and so straining
the Server) again. Since the pages are generated dynamically every time,
the timestamp doesn't help much for IMS-requests.
Any ideas ?

Thank You in advance,
Patrick

-- 
***** Patrick Lay
****  ICQ#:3484723
***   http://titan.cs.bonn.edu/~lay
**    lay@informatik.uni-bonn.de
*     Fax: 089-66617-10583