Wenkly Studio have sent in tips for Elven Assassin and Private Property since there is a way to set up local servers and prevent outside players from joining.
Here is the instruction: https://1e33ae0a-e8c2-40c9-ab9b-2efeaaf53121.filesusr.com/ugd/957014_6c3c0753a7a5425c98ab744f7a501712.pdf
Instructions are from Elven Assassin, but it works the same in Private Property.
