You do want to implement CUG on an Akamai level? I would assume that Akamai can do that, but I don't know how to implement that on Akamai. Technically you can use the same approach the dispatcher is using, but that might cause issues like additional latency from Akamai to the origin for cached data, also your publishs need to be able to scale so handle the amount of requests from Akamai for permission check.
Jörg