The antonym of "called together" is "dismissed" or "scattered." When a group of people is called together, it generally implies that they have been summoned to a specific place and time for a particular purpose. Therefore, the opposite of this would be when people are dismissed or sent away from that location, indicating the end of that purpose. Alternatively, the term scattered implies that people have dispersed in different directions without a common goal. When a group is scattered, it means they are not in one location, and there is no intention of calling them together.