I believe you have the right approach regarding the dependencies you want. There is no other way for you to limit the alerts constructively than by creating a group as a dependency, which is all the reason why SolarWinds created this feature. But with regards to the group not showing up on the All Groups view, its a great feature request as you can't do a filter right now with that view. Maybe you can try an Orion Report as an alternative? You can do some filtering there, although it's much less graphical, but you can have the status of each group displayed so it's worth a try.