usergroup permissions - please help

[Sculli]

I can't seem to get this right, and I realize that it shouldn't be too complicated. Please, if anyone understands what I am talking about, help me out, my users can't get to their forums. :disappointed:

My situation:

CategoryA
SubForumA
SubForumB
SubForumC
...

I have a lot of user groups, each user group is only supposed to have access to their SubForum, so UserGroupA should only have access to SubForumA. UserGroupA should also not know anything about the existance of SubForumB and any other subforums under CategoryA.

I have spend hours on this today and I can't seem to get the permissions right to achive this. Please see attached images.

If you even just have a wild guess as to what is wrong, please post, I am extremely desperate.

Edit: This was imported from phpbb2 using impex. The board works flawlessly for all those forums where the "registered users" have access.

Edit2: Basically I can have the users post to their forums IF I set view and post permissions for CategoryA. If I do that, then the UserGroupA, which is only supposed to see SubForumA, is seeing all subfora, and can probably read and post to all of them as well. That, of course, is unacceptable.

I don't quite understand why this seems so difficult to implement, in phpbb this was basically one drop down box that would set the permissions as to whether a user group has access to a subforum or not.