Many devices share the same limits, for example all freezer trucks. Instead of setting an alert on each device, set it once on a group.
Open Groups in the top bar.
Find the group and click + Set Alert in the Alert column.
Enter Min (<), Max (>) and, if you want emails, the Email recipients.
Click Create event.
The alert applies to every device in the group now and to any device you add later. On the device it shows as a group chip next to its own alert.
Change or delete a group alert
Click the group's alert chip in the Groups view, change it and click Save changes, or click Delete event.
Device and group alert on the same device
Both apply. Signal uses the strictest limits, and the chart shows both as dashed lines labelled device and group.