Remove licensing requirement for non-case Interact mailboxes

This is the functionality I would like:

I have a project. I want all email communication about this project between the business and IT to be tracked in Clarizen similar to TrackIt but without the requirement of the message originating from Clarizen. I want to use InterAct to do this. 

Only one team has Clarizen licences. You could consider the business to be a "customer", if you will. I want to be able to CC an email that I might send to someone in the business, who does not have any kind of license in Clarizen, and I want them to be able to reply, including that CC, and have their email and name appear in the emails section of the project.