Welcome to Geni, Lorraine I. O'Dell.
Instead of creating separate mailing groups on Yahoo, you could do the same here on Geni. Just create a Project for each group of families. This way you can tie the project directly to the relevant profiles. Each project has its own Discussion area, which most people would probably prefer over receiving too many emails.
Check out the details description of projects: http://wiki.geni.com/index.php/Projects or the list of existing ones: http://www.geni.com/projects
You can also reach the list of projects, via the Research menu at the top of the page.