Can Privoxy conditionally forward requests that would otherwise fail?

Hi,

Is it possible that privoxy could be configured to only forward requests to
another proxy (e.g. Tor) if it's the case that the connection failed?
i.e. Can privoxy only deal with requests that fail on the normal internet
path?
i.e. Can privoxy forward requests to a proxy as an attempt to get a
connection going, because the unproxied connection does not allow the site?

The alternative is to setup a list of sites that should be proxied, and the
others not. But the first prize is the one that is "automatic" and tries to
proxy the request only on a failure to connect.

Cheers,