Thank you both for your responses. I see the method you have used, AliGW, creates the list from the people listed under a certain date, but I have an existing list that I wish to search against, so it will not work for me. Quang's method works exactly as I want, so thank you for that, I have added reputation. I have not come across the Aggregate function before, so I will be reading up to understand how it is working.