In this paper we present a new visuo-haptic interaction mechanism for human-robot formation control. The formation setup consists of a human leader and multiple follower robots. The mobile robots are equipped only with RGB-D cameras, and they should maintain a desired distance and orientation to the leader at all times. Mechanical limitations common to all the robots limit the possible trajectories that the human can take. In this regard, vibrotactile feedback provided by a haptic bracelet guides the human along trajectories that are feasible for the team by warning him/her when the formation constraints are being violated. Psychophysical tests on the bracelet together with real-world experiments conducted with a team of Pioneer robots show the effectiveness of the proposed visuo-haptic paradigm for the coordination of mixed human-robot teams.