
Use Power Automate and create a trigger: “When an event is added, updated or deleted” from Outlook
Add a condition to check the subject contains your keyword
If YES, create the event in the Group Calendar
Save both IDs (Outlook event ID + Group calendar event ID) in a SharePoint list or Dataverse table
If event is updated, use the saved ID to update the matching Group Calendar event
If event is deleted, use the saved ID to delete it from the Group Calendar