I got the following message on the Unsolved Mysteries Wikia site; if anyone recognizes it, please let me know:

I am trying to determine if a show my mother saw years ago was on Unsolved mysteries. It was about several siblings who had been separated and sent to an orphanage in Missouri Valley, Iowa. This was sometime between 1930 and 1940. Gradually, they separately found their mother's grave and began leaving messages on it. They found each others messages (sometime in the 1980's or 1990's) and reunited. This episode is important to me because it was my mother's family that originally took the baby of this family it after the mother died. Some of my mother's siblings (now in their 90's) have seen the program, but some haven't. It would be great to order a copy of the episode.

Thanks for any help you can give me.