When you select a group Hyperglance shows you the group dashboard with 'Summary', 'Attributes' and 'Alarms' tabs. The 'Summary' tab is initially what you see and gives you a list of all the entities contained within that group:

You can adjust the summary from showing you a list (as above) to displaying donut charts about the alarms of the entities or about the running state of the entities:

In the next figure you can see the donut chart for "Account" nodes.
The big number in the center of the donut is the total number of Account entities that belong to that group.
You can also see the percentages of entities based on their current Alarms or runtime states by clicking on the button at the top of the donut list. "Alarms" is selected by default.
In this example the group has 3 Accounts, out of those 2 have Alarms of type "Warning" and  the remaining 1 is OK (No Alarms present):

If you hover over a section of the donut you will see be able the see the percentage of nodes  represented by the actual number.

You can click on any entry or donut chart in the summary tab will display an inventory table listing all corresponding entities contained with this group:

You can conduct advanced searches against this table which is explained in detail here