In order to reduce traffic congestion and to make actions more in sync, I want to use groups like it is possible with ZigBee.
However, I just can’t figure out how this works in Z2M. There seems to be no option for groups. How are groups handled in Z-Wave in general.
Basically, I want all lights and all covers in groups to quickly switch off all lights and to close all covers.
Is there any specific reason you don’t use the Groups feature in HA: Group - Home Assistant?
I think they have both light and cover entities and you are able to hide the “child” entities.
I don’t use groups in Zigbee2MQTT so I might be missing a trick here.
I thought these groups don’t have the advantage of sending just one command to multiple devices.
Please correct me if I am wrong on this.
When sending an action through an automation - you target the group entity rather than the individuals. So for instance you want to turn off the group of lights, you just select that as your target. It generates a new entity to send commands to. I even nest groups in groups - for example here is my all lights group:
Made up of these groups:
And then in the room groups, I have the final entities:
So I just target the group entities. So here is the All Lights entity:
But what happens in the background if you send “on” to “All Lights”. Will your controller send one signal or ten signals?
== 4 days later ==
EDIT:
I misread the title of this thread. As davinci pointed out below, his question was about z-wave / zwavejs2mqtt, not zigbee / zigbee2mqtt.
So what I said here was 100% off-topic.
=== original post ===
@BlackCatPeanut - While you could group lights in HA, and manage them together, the commands in the background, via zigbee mesh, would still be individual.
Back to the topic, @davinci , I believe the “groups” setup is right there in the top menu bar… would this help?
Maybe @davinci could help us test both… There should be no conflict if you have both… Just to be sure we are not missing anything.
It’ll be 10 turn on events. I use multicast for this. The group association is limited and based on your hardware in zwave. Some hardware can’t handle it. Mutlicast works regardless.
Here’s a script I wrote. Probably could be turned into a blueprint but I haven’t done it.
Groups in Zigbee are working perfectly. I created the groups in ZigBee2MQTT. What I want to do is the same thing in Z-Wave. 
I will have a look at the multicast.
If you have all ‘normal’ switches and lights. The script ends up making 2 calls, 1 for lights, 1 for switches. It’s a broadcast, so all lights will turn on at the same time and all switches will turn on at the same time. Sometimes you’ll get errors, but you can ignore them. Either way, they all turn on and off at the same time. No lag or ‘waterfall’ effect.
I run the switches second because the lights take time to ramp up and it makes them look like they all turn on or off at the same time.
Is there any downside of using multicast? For example does it retry if one of the devices didn’t respond?
No it does not.
Only if you have a poor mesh.
