If you are ready to manually edit/update permissions per .php file without any user interface for administration, yes you can just insert:
PHP Code:
require('./global.php');
at the begining of your .php file (assumed its in the forum dir), then check the permissions with "if" commands like:
PHP Code:
if ($bbuserinfo['userid']>0)
{
//do something
}
else
{
//do another thing
}
etc.