I'm looking for a way to detect and display other cases with the same value in the Web Email field. We don't use contacts for web-to-case, so I can't just display a related list of cases belonging to a contact. I know SF just released the case merge function, but that only works from a list view - it doesn't help me when I'm looking at an individual case.

This seems like something that should be possible on a Lightning page layout, but I can't figure it out. Thanks in advance for any ideas!