There are a lot of apps available with your Office 365 subscription. Yes outlook groups are no longer functional but Teams are a handy way to collaborate not only with colleagues but students as well. I have had a recent dialog about sharing calendar and have been reviewing the Planner App. “With Planner, team members can create plans with assigned tasks, and then add automation such as setting due dates that send out reminders and notifications, updating the status of the project and individual tasks, easily sharing and collaborating on files.”
Here is a link to a plan I created if you want to see how it works. Some options given is to view in Teams, add to Outlook calendar, share files, see progress charts, create “buckets” of items.