[Red Hat Satellite 6] How to limit/restrict the hosts from using a subscription which is not part of the activation key

Issue

• Systems registered with Red Hat Satellite 6 using activation key (AK), does not always honour the subset of subscriptions attached to the key - any other subscription outside the AK can be attached to the system.
• Systems registered with Red Hat Satellite using AK can automatically consume subscriptions not part of the key when auto-attach is enabled on the activation key.