We introduce a cooperative co-evolutionary system to facilitate the development of teams of agents. Specifically, we deal with the credit assignment problem of how to fairly split the fitness of a team to all of its participants. We believe that k different strategies for controlling the actions of a group of k agents can combine to form a cooperation strategy which efficiently results in attaining a global goal. A concern is the amount of time needed to either evolve a good team or reach convergence. We present several crossover mechanisms to reduce this time. Even with this mechanisms, the time is large; which precluded the gathering of sufficient data for a statistical base.