as i wrote earlier, your "instance" is your "home" while the federated network is your neighbourhood. you communicate with members of your home like @john but with your neighbours as @john@neighour . you can ask your home "manager" to block someone is someone is doing something naughty and if a neighbour is doing something naughty, you can ask your "manager" to block their access to you home, like closing your own blinds. if the offending neighbour gets really loud, your "manager" can have a restraining order banning them from coming to your property.

you can talk to your home members, your immediate neighbours, your neighbours on the other side of the city or the state, whatever....

does that make some sense?