In many fields and even in our daily life, besides the usual feedback controls, it is also very useful for us to control our business by regulating the connections among the subsystems directly. In this paper, the problem of a kind of synergic control among a collection of vehicles performing a shared task using intervehicle communication and internal output feedback are considered, in which the weights of the corresponding edges are considered as the control variables and called connection coefficient gain in this paper. Firstly, when the weights of the corresponding edges are fixed, necessary and sufficient conditions for stability and stabilizability under a special decentralized control strategy are given for the corresponding closed loop network system. Corresponding controllers design methods are proposed via the parameter-dependent Lyapunov function. Especially, two types of networks, star-shaped networks and globally coupled networks, are studied in detail. Secondly, the Nyquist criterion is presented, which uses the eigenvalues of the weights matrix to determine the effects of the connection coefficients regulation on system stability. Thirdly, a general description of this kind of synergic control is proposed via the block diagram of the information flow. Finally, the synergic control among a collection of vehicles with different linear dynamical model is investigated simply.