The used approach on Dragon does not support team-accounts for multi-player-games, though the team-data is preserved (like the average start and end rating and who was on the teams). This means, there is no explicit history of the accomplishments of teams like a team-rating. This would make no sense for Zen-Go anyway, only for Team-Go.
 
The current approach has been chosen, because of easier implementation avoiding all "team"-related stuff like ratings, team-handling, vacation-issues, etc.