The task of formation maintenance is of great importance in high level applications being executed by multirobot systems, such as exploration, surveillance and cleaning, among others. This article presents a strategy for formation maintenance in a group of mobile, cooperative, homogenous robots, which work together with a software agent known as ¿virtual robot¿. This virtual agent acts as reference for the spatial localization of each robot, and facilitates the navigation tasks of the group. This approach combines the characteristics of other well known formation reference strategies: leader- and unit-center referenced formations. The processes of validating this strategy was obtained from both simulated and real multirobot systems.