This paper demonstrates that the efficiency of Virtual Organisation (VO) creation by Collaborative Networks (CNs) can be limited by the complexity of the network itself. The authors previously proposed the use of distributed Enterprise Engineering methods based on Extended Axiomatic Design Theory to limit the complexity of VOs, and of the CN itself. This paper formulates methods to calculate and reduce the structural complexity of CNs and the cost of VO creation transactions through virtual brokerages. The method is demonstrated through an example and also yields a heuristic rule regarding the optimal size of such brokerages.