In this paper we analyze the objectivity of the peer review process of research performance by research groups in the scientific and technological Valencian system, over the period 1998-2002. For that purpose, we use qualitative indicators to assess wich of them are the most important to determine a research group as excellent one, based on peer review evaluation methodology. The results show that excellence appears to be driven only by publications in SCI/SSCI and the number of sexenios, and suggest that the peer review process is not as objective as we expected.