You can't do that, the permissions system isn't flexible enough, and the system will fight you. Eg, pulseaudio runs as the logged in user, and your firefox won

You can't do that, the permissions system isn't flexible enough, and the system will fight you. Eg, pulseaudio runs as the logged in user, and your firefox won't be able to talk to it. No youtube for you. Once you figure out the flexibility needed, you're back to SELinux pretty much.