While they can all be in the same group, they can also be in different folders. Folders in AirWave are meant for viewing.
That way you can have your universal view in the groups tab, while having a more modular view in the ap/devices folders view. Also note that in the ap/devices view -> you have an option to view the Top level, and expand to show all devices in the tree.
Example:
Group:
1) all devices
Folder:
1) ap group 1
2) ap group 2
Then when you view Clients, you'll be able to see the current client count next to the folder tree:
-To do this, go to ap/devices, at the bottom of the screen is the option to add folders. Create 2 folders for each of the ap-groups.
-Then go to Groups -> and in your group, create a new view that shows the ap-group, sort on ap group
-then you can use the modify option to pick all the APs in ap-group 1 and assign to a folder (save/apply).
-then repeat for the devices in the other ap-group
-when you view ap/devices, you should see all your APs split between the 2 folders (any remaining devices can sit in the top folder)
-and when you view clients, you'll see the new folder tree displaying client counts as I showed above