I'm hoping to move my group from yahoo to groups.io shortly, and the subgroup feature is a powerful motivator. However I really need to build on that structure to further organize and streamline the various functions of my group. An example:
If we had this structure, all items for the April, 2018 meeting including conversations would be contained in a subgroup that is easy to maintain. This would cut down on hundreds (or thousands after a year or two) of emails in the Meetings subgroup that can be hard to search and maintain.
We currently have dozens of yahoo groups that I plan to bring under one umbrella, but a natural subgroup hierarchy would make life so much easier than having 1 level of (again) dozens of subgroups and growing every month.