JUSTICE is one of the Twelve Righteous Virtues, which are explained in the MAN section of this web site.
Groups are communities of people with similar interests or lifestyles in common. Browse around! Some are private so they require acceptance by the moderator - but those are just to make sure, for instance, that you are a Woman wanting to join the Woman group. This should be obvious by your username if you logged in with Social Media. Don't see a group you would like? Create your own!