The best replacement for groups is teams.

The best alternatives to groups are rated as following:
★★★★★  teams
★★★  periods
★★★  pages
★★  individuals
★★  political parties
★  organizations
★  yahoo groups
★  roles
★  segments mailchimp
★  clubs
★  google groups
★  group's
  team
  secondary groups
  out groups
  pages facebook
  lists mailchimp
  surveys
  blocks autocad
  group's grammar
  individuals decision making
  groups'
  sunday school
  closed groups
  homogeneous groups
  clicks
  work teams
  guided reading groups
  universal groups
  therapy groups
  duos
  periods periodic table
  social movements
  individual interviews
  fan pages
  lists
  cliques

Your alternative for groups is not listed? Suggest!
Speaking about groups, one probably shouldn't forget about most members on facebook.

Other search terms related to groups and their ratings are:
★★★★★ most members on facebook
You have in mind a companion for groups and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of groups in all years. Click on graph for more.
groups
teams
periods