The emergence of new networking research organisations is explained by the need to promote excellence in research and to facilitate the resolution of specific problems. This study focuses on a Spanish case, the Biomedical Research Networking Centres (CIBER), created through a partnership of research groups, without physical proximity, who work on common health related issues. These structures are a great challenge for bibliometricians due to their heterogeneous composition and virtual nature. Therefore, the main objective of this paper is to assess different approaches based on addresses, funding acknowledgements and authors to explore which search strategy or combination is more effective to identify CIBER publications. To this end, we downloaded all the Spanish publications from the Web of Science databases, in the subject categories of Gastroenterology/Hepatology and Psychiatry during the period 2008-2011. Our results showed that, taken alone, the dataset based on addresses identified more than 60 % of all potential CIBER publications. However, the best outcome was obtained by combining it with additional datasets based on funding acknowledgements and on authors, recovering more than 80 % of all possible CIBER publications without losing accuracy. In terms of bibliometric performance, all the CIBER sets showed scores above the country average, thus proving the relevance of these virtual organisations. Finally, given the increasing importance of these structures and the fact that authors do not always mention their connection to CIBER, some recommendations are offered to develop clear policies on how, when and where to specify this relationship.