Thats a good idea with better groobs! But why? Thats are LANDINGPAGES for Google! I created on my site some groops and I can see that I get a lot of users througt the groop. Thay came to my site from the url of the groop indexed by google! So i sad it in the past LANDING PAGES are so important for SEO. And each group is a landing page, if you are working on this idea its great!

One good idea is to create groops of people from different cities and countries splited in man and woman. Thats would see more be powerfull landing pages and groups for google!!!!!!