Help making visiblity work

So there was this request for a plugin with appartments, and i want the players who have the same appartments to not be able to see each other and every one in the party too,
so i have 2 maps one

Code:java

private Map<Player, Integer> ina = new HashMap<Player, Integer>();

and the second one

Code:java

    private Map<Player, Player> inao = new HashMap<Player, Player>();

so the first one contains the owner of the appartment and the appartmentid
and the second one contains the player that has joined someone elses his appartment and the player who is the owner of the appartment

i hope i made that clear, that said i want every owner in the first list to not be able to see eachother
every one thats not in any of these list cant see the players who are in the lists
and every one in someone's appartment should be able to see eachother
so i hope you guys understand becuz i was brain crushed!

 

You wouldnt need an Apartment ID, You could create a Hashmap with the Apartment Owner (String to prevent data leaking) and then ArrayList<String> as the value.
Never tried it but I know you can.

 

i know its not supposed to be players in a list but the list are cleared and stored regulairly and i need the appartment id's for something else the problem is that i have to have every one in the first list invisible to every one except the one's he invited to his appartment