My great-grandmother had 9 children. She had these 9 children with 4 different mates. When constructing my family tree do I just work on my biological great-grandfathers branch or do I work on all 4 branches. I have a family reunion happening in August of next year, and all descendants of my great-grandmother will be attending.

In order to be authentic you have to work on all 4 branches. I know it is a lot of work, but no sense in doing a family tree if you don't do this.