Working multiple horses simultaneously at liberty is one of the most advanced areas of horsemanship, requiring a trainer who has developed exceptional clarity and subtlety of communication, extensive experience reading herd dynamics, and individual horses whose liberty responses are absolutely solid before they are introduced to working as a group.
The starting point is individual excellence — every horse in the group must have reliable liberty responses individually, including send, draw, direction changes, and gait transitions. A horse that is only marginally responsive individually will be completely unreliable in a group where the trainer's attention is divided and herd social dynamics add additional variables.
Group liberty work is introduced gradually — starting with two horses whose individual responsiveness is solid and whose personalities are compatible, then working toward larger groups as the trainer's ability to read and influence the group develops. The trainer must learn to use spatial position and energy to direct individual horses within the group without inadvertently cueing others, and to read which horse is about to break gait before it happens. Elite practitioners who demonstrate six or eight horses simultaneously have typically spent years developing this skill.