Invisible room, somehow still visible?

Essentially what the title says, i'm creating a room as a "PRIVATE" room, where it is open but not visible, and yet people weirdly enough can join using JoinRandomRoom(); which is an absolute NOPE for the intended behaviour.

Context: What we want to achieve is for the player to be able to create a "private" room so they can invite their friends, While the room is hidden from the public but it can be access by the room name (which is already known by the master).