The Group Exercise is one of the tasks in the Assessment Centre that is compulsory in all Administrator (AD) profiles. This means that groups of 3-6 candidates are required to take part in a simulation based on a background file that all of them must read and then try to come to a conclusion within 30 or so minutes.
Assessors are not part of the group exercise and they only observe the individual behaviours, leadership, analytical and communication skills of each participant.
See also:
Assessment Centre, Oral Presentation, Administrators (AD), Leadership, Working with Others
Related link:
EPSO Assessment Centre Insights, EPSO Classroom Training Sessions, Personal Coaching Sessions