I have been tasked with creating a calendar in a root site that get's updated from child site calendar events. I am able to access the Calendar List from the parent site in the child site's to add an event. However, I'm having trouble finding a way to create a uniqueIdentifier for the event so that when the child calendar's event is updated or deleted, the parent site calendar get's updated as well. The ListItem ID field appears to be only unique among the site. I did find a UniqueItemId field, but apparantly it's read-only in the SP LIstitem object. Can someone please give me some guidance here? Many thanks!