Send a single email notification for multiple items with a matching date

We run a checklist of tasks that need to be done before a new hire start date. On the item level, we have the new hire’s information such as manager, department, and start date. On the subitem level, we have all the tasks that need to be completed as well as task owners. Right now, we have an automation that sends an email to task owners 1 week before the new hire start date.

Since we sometimes, have multiple new hires starting on the same day, it would be great if there was an automation that can look at the matching start dates and send an email with combined information instead of sending 1 email with the same information multiple times.