Changing the territory for an app update, will it prevent current installs from updating?

I have an app update ready for release, but for peace of mind I would like to test some of the new features in the live environment before I release to all my users (700+). If I disable all territories but mine and my developer's will that prevent those that already have the app in other territories from seeing the update?

It would be nice if Apple would create a "dev territory" to test things before releasing to everyone. I know I should test in the dev environment, and do, but there are still a lot of things unclear when moving to the live environment and since it takes 1 week or more to get a fix out it is really stressful.

Just thinking of this as a work around - is it possible?