I feel like this one might be a challenge but what I think this plugin needs is per permission scoreboards. Adding multiple scoreboard settings in the config and assigning them to an permission (like scoreboardstats.use.scoreboard1). This would be great if you want to show a rank one set of variables and another rank something completely different. This can be a config example http://pastebin.com/LYEQu6Ya

If the group/player has multiple scoreboard permissions, the plugin can just copy items to the first scoreboard thats being used.