This videos show a method for cooperative manipulation of an unknown load with a group networked mobile robots.
The method is described in this paper:
Petitti A, Franchi A, Di Paola D, Rizzo A. Decentralized Motion Control for Cooperative Manipulation with a Team of Networked Mobile Manipulators., 2016 IEEE Int. Conf. on Robotics and Automation., Stockholm, Sweden; 2016. pp. 441-446.