How to add siblings and children of my ancestors to a tree without adding them all by hand

I'm in the process of moving the contents of my tree (Ryne/Nesbit family tree) over from ancestry.com . I also have a MyHeritage account but it has a partial tree that I have not kept it up-to-date. On Geni I have entered all my direct relatives through my 2nd great grandparents. Now I want to add my relatives' siblings, e.g. my grandparents brothers and sisters, or equivalently all of a great-grandparents' children. Do I have to do this by hand? Geni finds records over on MyHeritage (e.g. a census record that includes children) that I've confirmed but the matches don't appear to add anything to my tree on Geni.