A group of agents is faced with collective decisional problems when trying to solve a complex problem together. The agents must cooperate to efficiently establish which alternative appears to be a convenient consensus. The corresponding debate is seen as dynamical process that we propose to analyze and control. Its dynamics depends on the strategy the agents argue their choices and on the intervention order in the debate. The influence an agent may have upon the other ones may appear as a disturbance in the deliberation process except if it is used to control the debate dynamics.