Since I use Cyjon's Townie tenants, I don't have any Social Groupies, and therefore none of their special greetings and such...
Well, Marhis (may her tribe ever increase) has "gizmos" which allow any playable to be considered a member of a Social Group.
In addition, Boiling Oil (may his tribe ever increase) of Simbology and Leefish has created an awesome hack, Social Group Greetings v1.02, which allows playables to greet other members of their Social Groups. Full description here.
My brilliant (?) idea was to give both my Custom townies, Downtownies, etc. and my playables one of Marhis' gizmos at creation, then let them interact as if they were also Social Groupies.
Only thing I still have to figure out is how to choose the Social Groups. So far, I've decided to use their clothing, LTWs, skills, or Aspirations as "clues".
Obviously, Socialites would wear evening gowns as everyday, Bohemians would dress like hippies, Jocks would wear activewear as everyday, but I'm having a little trouble deciding what types of clothes should differentiate between Gearheads and Techies (since my Groupies vanished as soon as I nabbed Cyjon's hack). I guess Gearheads like to get their hands dirtier?
In terms of Aspirations, I'm thinking Fortune and Popularity Sims could be Socialites, Knowledge Sims could be Techies or Gearheads...
Skills... good Body skill would indicate a Jock, high Creativity skill Sims could be Bohemians...
Careers and LTW, Scientists are obviously Techies, but where do Slackers fit in?