In this paper we investigate whether we can extract the commonalities shared by a group of cover songs or versions of the same musical piece. As a main contribution, we introduce the concept of cover group thumbnail, which is the most representative, essential subsequence for an entire group of versions. Opposed to previous approaches, we jointly consider all versions of a given song to compute a single cover group template, which then shows a high degree of robustness against version-specific aspects. To compute such a template, we introduce a modification of a recent audio thumbnailing technique. To evaluate the reliability of our conceptual contribution, we consider the task of template-based version identification, where we show comparable accuracies to existing systems.