Many scientific collaborations have a central calendar, often hosted on Google Calendar, to coordinate Teleconferences, meetings and events across timezones.
The issue
Most users are only interested in a small subset of the events, however Google Calendar does not allow them to subscribe to single events. The central calendar admin could invite each person to events, but that requires lots of work.
So, users either subscribe to the whole calendar, but then have a huge clutter of un-interesting events, or copy just a subset of the events to their calendars, but loose track of any rescheduling of the original event.
Proposed solution
I recommend to split the events across multiple calendars, for example one for each working group, or any other categorization where most users would be interested in all events in a calendar. And possibly a “General” category with events that should interest the whole collaboration.
Still, we can embed all of the calendars in a single webpage, see an example below where 2 calendars (Monday and Tuesday telecon calendars) are visualized together, see the Google Calendar documentation.
Users can click on the bottom “Add to Google Calendar” button and subscribe to a subset or all the calendars. See the screenshot below, 
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As an additional benefit, we can compartimentalize permissions more easily, e.g. leads of a working group get writing access only to their relevant calendar/calendars.