How do I....Usergroup..? Subscription?..Hack?

[Jordan17]

I want some sort of system where a member can go into their UserCP and "subscribe" to a certain "thing". Basically, I have a Fan Fiction seciton on my forum, within that section there is a 16+ part for fan fictions that contain strong language etc.

How can I block access to this forum for everyone, apart from those peopel who go into their userCP and subscribe to it - those people will be allowed access.

If there any way to do this?

[gpc1900]

make a new usergroup.there is a option to make it joinable.
change forum permissions to just allow that usergroup.
they can join in the cp,but i think it has to be aproved in 'join requests'