Cooperative negotiation is proved to be an effective paradigm to solve complex dynamic multi-objective problems in which each objective is associated to an agent. When the multi-objective problem is defined on several continuous variables, cooperative negotiation can be traced back to a sequential bargaining. However, the complexity of highly reconfigurable scenarios with a large number of agents does not allow the adoption of classical game theory techniques to design optimal bargaining models for cooperative negotiations. A way to tackle this complexity is based on the decentralization of the system, usually obtained by introducing a mediator that reduces the amount of information directly exchanged between the agents. In this paper we present and experimentally evaluate a decentralized bargaining model for cooperative negotiation on multiple continuous dependent issues able to produce approximate Pareto optimal outcomes.