Hello - I am an ancestor of William Mars who was a steamboat operator out of Gainesville, Mississippi. He had a brother, John, who was a doctor in the area. His daughter, Mary, is my great-grandmother - she never married but had a bunch of kids including my grandfather - Leon Mars. I am trying to find out if William and John had other brothers and sisters and who their parents were. I am hitting a dead end with this branch of the family. Thanks for any help!