I want to play my ps4 offline at my friend's expense
Why not just play with your online friends?
I want to play in a different network in this house
Sometimes it is just nice to play games by yourself, or as part of a group who are together in a house. You should just let your usual group know you want to play alone for a while and then join back up when you are ready to be social again.
They are my friends, they should know.
You're right, your friends should probably recognize that you want to play offline for a little while, so this shouldn't be a big deal.  Just let them know that it's not because you just wanted something different, and not because you don't want to play with them anymore.