Any way to block all traffic on a particular app when not routing through Meshnet?

I use Meshnet to route my traffic through another computer I have at home, typically while using a certain app. I have the kill switch on for this particular app, but for extra security I'd like to make it so that absolutely no traffic can get through when I'm not specifically connected to that computer. Is there a rule I can set on Windows Firewall? To be clear, I don't want to block all traffic period, but only for this one program.