I once had to send out personalised emails for a large client in Portugal. We couldn't handle sending them out one by one, but we found out that there was a 50%

I once had to send out personalised emails for a large client in Portugal. We couldn't handle sending them out one by one, but we found out that there was a 50% chance for at least two people to have the same name and surname. So we bundled together people with the same names and then managed to overcome the bottleneck.