Collaborative behavioural monitoring (CBM) is becoming an increasingly popular solution used in complex and large-scale systems such as a system-of-systems (SoS). It has the ability to overcome the challenges associated with monitoring behaviour in the distributed, decentralised and dynamic environment of a SoS. However, the effectiveness of this approach depends upon the similarity of structural and operational characteristics of components selected for collaboration. Due to the scale and diversity of a SoS, accurately selecting similar collaborative components is a difficult task. Currently, existing selection methods are ineffective when comprehensively assessing the similarity of components, thus presenting a potential flaw in the use of CBM. In this paper, we propose a method to improve the initial selection process of CBM components. Our method offers a superior level of similarity and benefit comparison, than those offered by existing methods. Our experimental results presented in this paper highlight the increased efficiency, reliability and assured validity of the resultant CBM setups.