Integrated Events Calendar

Is there a way to have a calendar where we can fill in events in the city, key dates, etc.

This to then be integrated into the collins calendar so it shows up above/under notes.

When an event is filled in, there is to be an option to select which site will show this on their collins diary.

Currently, with key events, we're having to write them multiple times over across multiple sites in the notes section, so everyone is on the same page for what events are going on that day. It's a lot to keep up with!