Whitelist functionality analog to ignored_environments.yml

Hi,

Is there a way to provide a whitelist of classes that should show up in
foreman. I know I can blacklist with ignored_environments.yml
but in my case I would rather specify a whitelist where only roles can be
assigned (following the roles and profiles approach
http://garylarizza.com/blog/2014/02/17/puppet-workflow-part-2/)

Thanks and Regards,
Patrick