I'm just another admin and have a few ideas, although I don't understand the use case.
You said:
You want to redirect (to a mailbox, connector, etc) an entire email if any of the recipients are "outside of the organization". Said inversely, you want to redirect an email if all of the recipients are not "inside the organization".You want to redirect (to a mailbox, connector, etc) an entire email if any of the recipients are "outside of the organization". Said inversely, you want to redirect an email if all of the recipients are not "inside the organization".
But those two things are not the same. Do you mean to say for the second version to redirect an email if ANY of the recipients are not "inside the organization"?
Regardless, I would recommend setting up this type of logic with mailbox-level rules. Additionally, I would strongly recommend forwarding instead of redirecting email that arrives externally and is sent externally.