Aggregate/hierarchical groups

One nice feature of Zimbra is that groups can be defined in terms of other groups. If I have user Justen I can add him to 'crowd-support', and then create a group 'support' that includes 'crowd-support', 'jira-support' and 'confluence-support'. It would be nice to be able to do this in Crowd rather than having to manually maintain this hierarchy.

An additional related feature of Zimbra is the ability to 'drill-up' into these groups; when you view the user's group membership you see two lots; a "Member of" pane (which would show 'crowd-support''), and an "Indirect Member of" pane (which would show 'support').