Say I have a forum that discusses games consoles and a user registers selecting that they own a PC and Xbox One. I'd like that only categories relating to those 2 subjects be shown to a user and the rest say the PS4 category will be hidden from a user. A user should be able to change what they are allowed to see at any time in their profile. Does anything like this already exist? I'm thinking a custom field with a callback to place a user in a certain category(s) which cannot view certain forums. Would this suffice?