Route::set('admin', 'admin(/<controller>(/<action>(/<id>)))')
   ->defaults(array(
      'directory' => 'admin',
      'controller' => 'page',
      'action' => 'index',
   ));

class Controller_Admin_Main extends Controller_Admin_Common {
    public $secure_actions = array(
        'index' => array('login', 'admin'),
        'root' => array('login', 'admin', 'root'),
        'noaccess' => array('login')
        );
    public function action_index()
    {
        $user = Auth::instance()->get_user();

        $users = ORM::factory('user', $user->id);
        $roles = $users->roles->find_all();
        $role = $roles[count($roles)-1]->name;

        $this->view->content = Request::initial()->action($role)->execute();
        $this->response->body($this->view);
    }
    public function action_root() {}
    public function action_noaccess() {}
}

public function action_manager() {}

'manager' => array('login', 'admin', 'manager'),
'root' => array('login', 'admin', 'manager', 'root'),