One System,
Armed In Parts
Arming the whole house is easy. The real question is what happens when you want half of it armed and half of it lived in. That's what groups are for.
Most people run their alarm as one switch: the whole house is armed, or the whole house is off. That's fine until life gets more specific — you're asleep upstairs but want the downstairs watched, or a cleaner is in the kitchen while the office and its safe should stay locked down. One switch can't do that.
Ajax's answer is Group mode — sometimes called zones or partitions in other systems. It lets one system behave like several, each armed on its own. Here's how it actually works, and where it's genuinely useful.
The Mechanics
What A Group Actually Is
A group is simply a named set of your devices. You turn on Group mode in the Ajax app, then assign each sensor to a group — "Upstairs," "Main Floor," "Garage," "Office." From then on, each group can be armed or disarmed independently of the rest of the system.
Two honest rules worth knowing up front:
- A device lives in one group at a time. Each sensor belongs to a single group — assign it to a new one and it moves. Clean and simple, no overlaps to untangle.
- Your hub sets the ceiling. The maximum number of groups depends on your Ajax hub model, so how finely you can divide the house is a function of which hub you have. Worth knowing before you plan a dozen areas.
Once groups exist, the app shows the whole picture at a glance — everything armed, partially armed, or off — and each area arms with its own tap, schedule, or keypad.
Where It Earns Its Keep
The Situations One Switch Can't Handle
Live In Part, Watch The Rest
Arm the garage and the basement overnight while the bedrooms stay disarmed. Or watch the whole main floor while the family is upstairs. The lived-in part stays quiet; the rest is guarded.
The Cleaner Problem
A cleaner or contractor needs the kitchen and living room — not the office or the safe. Put those in their own group and keep them armed while the rest of the house is open for work.
That second case points at something powerful: access can be scoped to a group. An Ajax keypad code can be limited to specific areas — so a cleaner's code disarms the common space but has no power over the office group at all. You hand out access to a slice of the house, not the whole thing, and the log records who did what.
Don't Confuse The Two
Groups Are Not Night Mode
It's easy to mix these up, so plainly: Night mode is a separate feature from groups. Night mode is a partial-arming mode built for one specific job — arming the perimeter while people sleep inside, so the doors and outer sensors are live but you can move around indoors without setting it off.
Groups are about dividing the space by area; Night mode is about arming the edge while you're inside. They work alongside each other — most homes end up using Night mode for bedtime and groups for everything else — but they're different tools solving different problems. A good system design uses both where they fit.
Getting It Right
The Layout Is The Whole Game
Group mode is configured in the app, so it's not a hardware purchase — it's a design decision. And that's exactly where it's easy to get wrong. Groups that don't match how you actually live become friction: too few and you're back to one switch, too many and arming the house is a chore.
The right layout comes from how the house is really used — who's home when, which spaces need independent control, where access gets handed to other people. That's the part we design with you, so the groups feel obvious instead of fiddly. It's less about the sensors and more about the map they're arranged into.
Keep Reading
Related Guides
- How a wireless alarm system works — the hub, the sensors, and how it all fits
- App, keypad, or fob? — the right control for everyone in the house
- How many motion sensors you need — why it's fewer than you think
Want The House Divided
The Way You Live In It?
Tell us how the house is used — who's home when, what needs separate control, who gets access to what — and we'll design the group layout to match. It's part of how we design every system.