A method and system are disclosed for creating portfolios of requests so as to reduce or minimize the variance in the workloads generated by those requests. The invention also takes into account the throughput of the servers that are servicing the requests. In a preferred embodiment, the method comprises the steps of establishing a set of system parameters; using said parameters to generate a model, said model including a defined optimization problem; and solving said optimization problem to output a set of mixing weights. The set of parameters and said mixing weights are used to generate a task; and the service requests are distributed to different service teams according to the generated task. Also, for example, the distributing may be done by distributing requests of type i to team j with weight proportional to wij.