Parentgroup as condition in e.g. Overviews

1) Description
I want to be able to use a parent group as a condition, instead of having to add multiple groups that are all within the same parent group into an overview.

2) Reallife-Example
We create IT-Networks on different events. For each event we create a group that, beginning with release 6.2, has the parentgroup Event. For each Event I (as the Admin) would have to create a new Overview or edit an existing one. But if I would just be able to specify the condition “parentgroup = Event”, I could just have one overview that my coworkers would have access to, in which the open tickets for the current events would be in.

3) Why not use already implemented possibilities
A possibility would be, to just use group for events, but not every coworker should be able to see every ticket for every event. (We have Events, where we have to sign NDAs).
Another would be, to manually add the groups manually to the overview, but that’s the point I am trying to get rid of and automate.

4) Expectation
Beeing able to use a parentgroup as a condition in overviews (and triggers, etc.) instead of having to put in every group manually.