Yeah that's what I figured, thanks!
Do you know if there's any way to extend this so that I can monitor a group for other triggers, such as high ram or cpu usage?
When I set an alert on a group or group member I can't see an option to set CPU load as a trigger. I'm not sure if I need to define another type of custom property or just a different type of alert
Found this in another post and it may be similar to what you're aiming to accomplish - Source posted below
This can be achieved by using custom properties at the node level. This same feature can be used to create a dynamic query for the group membership.
1. Go to settings -> Manage Custom Properties.
2. Create a node based Custom Property called something like server_group
3. Assign a value to each node such as "Group A", "Group B" etc (this can be done later from Settings- > Manage Custom Properties -> View / Edit Values
4. Create your alert such as "Alert me when CPU is high on server group A" using the custom property so that the trigger condition includes the custom property you created.
5. You can now create a group using a dynamic query using the same custom property for the group members.
Source: Alerts for Group Members
Yeah that's what a found when I looked into it further. I didn't realise that creating a custom property allows you to create sub groups that you can add nodes to.
Thanks for all your help!