This is how I operate, compartmentalisation.
I recommend not mixing too much, as it simplifies the social dynamic.
I don't use facebook.
I don't think of it like firewalls, becuase I have done it in such a way that they are not likely to cross paths anyway.
I don't control them, I wouldn't be able to to. They are free agents, and besides the majority of the time I'm not with people, as i get benefit from a small amount social interaction.