Widest range of Broker versions than can co-exist in a territory?

To facilitate our phased migration from 6.5 to 9.6 we would like to create a territory with Broker 6.5.2 and 9.6. Is it possible to have such a wide range of versions in the same territory? Or do we need to consider a two-step approach with an intermediate version such as 8.2?

Suggestion:

Create a Territory for each version and connect them via a Gateway allowing the documents to be routed in both directions.

Regards,
Holger

Thank you - that sounds like a plan. I will give it a try on my local development environment.