Having a robot that carries out a task for you is certainly of some help. Having a group of robots seems to be even better because in this case the task may be finished faster and more reliably. However, dealing with a group of robots can make some problems more difficult. In this paper we sketch some of the advantages and some problems that come up when dealing with groups of robots. In particular, we describe techniques as they have been developed and tested in the area of robotic soccer.