I'm trying to find a solution for a syndicated event calendar that allows for members to have a shared calendar that contains events from a collection of sites. It the trick to it though is that it needs a few things, each member can pick which other member's calendars get displayed on their site, as well visitors to the site need to be able to submit events from any of the member sites which need to be approved by a member before the event appears on the calendar. I know the event_calendar module does a great job of displaying events on a single site but events must be added by the administrators.

My client has requested the following:
- Should allow add/removal of 'groups': Groups can be community organizations, businesses, or political bodies - by a top-level administrator.

- Should allow each Group to login and manage their own calendar, adding/editing/deleting their own events. The event system should notify the user of 'other events happening on this day' (pulling from all Groups) when adding a new event.

- Should be syndicated (<script />) so that Groups can easily display their own calendar on their website.

- Should allow Groups to select which of the other Groups in the system will appear on their calendar (i.e. a long list of checkboxes of the other Groups, whichever are checked then appear in the syndicated calendar)

- Should allow visitors to the page containing the syndicated calendar to suggest events. Events suggested to a calendar are put in an approval queue, and become visible the next time that Group owner of that calendar logs in.

Has anyone heard of/is there a module for SilverStripe that meets these requirements?