Within Windows Firewall, if you set one network as a “Domain network”, and the other one as a “Home or work(private) network” (as I have it set up right now), you can turn on or off Windows firewall individually for each of these networks. You can drill down and set more advanced options too, but I’m not using it (it’s turned off for both), so I don’t care.
The point: just because you haven’t seen it doesn’t mean it doesn’t exist (let alone the fact that such a feature is rather ubiquitous). Also, telling me that I “just have to set the correct rule for” something without telling me how doesn’t help at all. It also doesn’t even address my original problem. It’s ok if you don’t know, you don’t even have to reply.
It is, however, another matter entirely if this is not possible in Avast. Are you implying that this can’t be done?