Connect Xenon to Mesh but NOT to cloud?

I have a project for which I will have one Argon and 20+ Xenons connected to a single Argon for network connectivity. I would like to have the ability to have the Xenons connected to the wifi network through the Argon, but disconnect all of the devices from the cloud (because this application will not have a reliable internet connection).

Is there a way to connect a Xenon to the MESH network (and pass traffic to a LAN) without being connected to the cloud?

I’ve read this:

And it appears that in order to connect to mesh, you have to be connected to the cloud also.

SYSTEM_MODE(SEMI_AUTOMATIC) ans Mesh.on with Mesh.connect() on the Xenons should do the trick for mesh only communication.
For the LAN only part you would need SYSTEM_MODE(SEMI_AUTOMATIC) with Mesh.on, Mesh.connect(), WiFi.on() and WiFi.connect().

Alternatively you can start in AUTOMATIC mode and then cut the cloud connection via Particle.disconnect() this will leave the underlying connections on.
However, that requires the cloud to be available at startup.