How to disable acces phpbb forums from drupal

I have plugged this module to a drupal 6.4 educational site. Evrything is working fine. But I need to limit the users to access the forums.
I have 02 groups (roles) for drupal called 'Athenticated user' (default role) and 'Accepted' role which I created. When user registre with the drupal user automatically added to Athenticated user group. So user automtically get acces to forums. But I need to access deny for this group to access phpBB forums.
But need to set access enable for 'Accepted' group. So I can add any user later to 'Accepted' group so they can access forums later but not in the first instance . Because I need to add only selected users to the forums.

If the inegration module appear in the drupal 'permission' page So i can allocate permission to that module. Is there any way to make available inthe permission page phpbb module or any other method to achieve this?

Thanks