Windows guest - how do I correctly edit the Windows Hosts file to prevent access to one URL?

I have a Windows 10 guest running OK in Parallels Desktop 13. All I want to do is append one line to my Windows Hosts file to create a loopback for one URL. My current network configuration is set to Shared, and it looks as if the local host is 0.0.0.0. But if I loopback the URL to 0.0.0.0, does Parallels loopback and block access to that URL, or does it simply make a connection through the host to that URL?

Thanks for looking