Redirect network of on url to proxy otherwise block it

I want to use proxy only for one website URL, and if the proxy is disabled or down, the URL blocked by a firewall So in my mac os, I connect to a proxy server somewhere, and then if I open, for example, google.com, all the traffic pass from the proxy, but if my mac os couldn’t connect to the proxy, google.com will be blocked by the firewall or anything else. is there any solution for that?
I want to open google.com by proxy of a Germany server when I’m in USA and other URL use default connection settings without any proxy to a server.
When proxy server is down, I want the google.com blocked by firewall or any other solution