Forum Topic Permissions

Hi there,
Is it possible to restrict the permissions of a particular forum category or topic?
Basically we have a social area, which is open to everyone, all can post and update conversions etc.
But we also have a forum that we need to restrict to a certain group of users?
Is this possible to combine the two?
I can see the conversation permissions but this appears to cover the global site.

View Replies:
Steevb replied on at Permalink Reply
Use normal permissions or 'Advanced Permissions'.
lightningd replied on at Permalink Reply
Hi there,
Thanks for that.
You'll have to excuse my ignorance, but where are these normal or advanced permissions set for forums/topics please? I've searched everywhere I can see/think but can't change anything specifically on the forum.