I want to disable the internet connectivity of 'Steam' as my younger brother keeps on downloading video games from the Steam client on my computer. I cannot downright uninstall it as well since his existing games would cease to function for the offline mode. So is there a way where the computer is connected to the internet but only 'Steam' is unable to access it?
For reference, we can disable internet connectivity for particular apps on Android smartphones using app settings. Is there a way for doing something like this on a Windows 8.1 PC?