Yeah, I figured that out too. I could not figure out how to group the live contact tiles. In Windows Phone 7 you can create a Contact Group within the People App. You can then save that as a live tile. An example is to make a contact group called Family. You can then add contacts from the People app to this group. From there you can have that group be a live tile (so you get a Live Tile for all the people in the Group.