Part of this will require an integration with Bunchball, which I know how to do some stuff, but in general you would need to setup a mission with a callback that can ping your add-on service letting you know that a specific user achieved the mission of "level 4".
When your add-on receives that trusted ping from Bunchball it can use the SecurityGroupService:
to auto-provision the person into the appropriate permission group, or whatever.
Does that help? This sounds like a great use of the Getting Started > Installing the Jive Node SDK