[squid-users] Dynamic Settings

I have been assigned the glory of trying to figure out a web filtering
idea. People would sign up for a free content filtering account.

Now here's the idea:

Everything currently goes through our squid cache, the acls are
configured to only allow the people in our network. From there, I want
to be able to, based on a database value of 1/0, be able to basically
set squid's proxy to a Dan's guardian server that we have running next
to it. Is squid able to do this? I know Dan's Guardian doesn't do
ACL's, and the service has to be transparent to the customer (to avoid
children disabling and such).

I guess my question is, based on a value in either LDAP or MySQL, can
squid proxy off of another server?

Thanks,
Derek