For setting up your cutom page use this https://github.com/NodeBB/NodeBB/blob/master/src/routes/helpers.js#L5, or at least use the middleware.pageView function as a middleware, that will count the pageviews.
As for only allowing some groups to view the page. You have check if the user is a member of those groups with the function groups.isMemberOfGroups(uid, ['group1', 'group2'], callback); You can get the uid from req.uid in your route handler.
