3 systems in one resi

We have a multi story mixed resi.
First floor, stairway, and common use exterior are one system.
Second floor brother family #1
Third floor brother family #2
Not planned for continual use as of now. Vacation beach property.

My question is best way to setup systems in particular the common area and more to the point the
access to change time clocks for the common area.
As of now it's unclear if the network will be one full system with subnets or three or two....?
Looking for advice to guide the owners if need be.
If they put the common area on brother #2 system but brother #3 is there and wants to control common area?
If they have to change to a diff WIFI to work each systems it may get a little confusing.

See where I'm going?

Thanks

They don't use WiFi at all. They use their own RF frequencies. If you have multiple systems in close proximity it's possible to change the frequency they use. But since each device is paired to it's own repeater that's not really much of a problem.

It'd only work if you used keypads/buttons to control the devices. As soon as you use apps you'd lose boundaries. With hardware keypads and Pico remotes you could program any of them to be limited to just specific devices. But an app is going to see all of the devices and timeclocks.

There'd be no problem having keypads and remotes in both locations controlling the common areas. Besides annoying someone, that is.

Where it gets challenging is dealing with away mode timeclocks. If all you want is an away mode to control the common area you're fine with one system. Anyone being in any of the levels would put the whole place into a 'home' mode. Going into an 'away' mode that wouldn't disrupt the other occupied spaces would be problematic. As in, if you want timeclock modes to 'fake occupancy' you'd have a HORRIBLE amount of programming duplication to wrestle with.

The short answer is "don't do that". Best to have one repeater for each level AND the common area. And then use Pico remotes to control the common area from in the three occupied areas. You'd probably need a keypad in the common area to select a Home or Away mode for it. Likewise one in each separate space.

The cost to use multiple systems is one time. The on-going cost to fight with programming multiple modes is likely much higher over time.

One thing you could do, with multiple repeaters, is use a 3rd party system and have that provide additional coordinating controls or a unified web interface. The same thing could be done with Caseta Smart Bridge Pro systems. Otherwise, using four separate Ra2 installations adds it's own kind of complexity when using only the Lutron apps.

This might a question worth asking of a Homeworks integrator. The cost upfront will be higher but the way a HWQS system can be programmed might be better suited for this application.

None of it will be cheap if you want to make the system reliable and not confusing to the occupants. Especially not with then possibility of them being rentals.

Mitch,
Come see me. I have an idea that might help.