<p>Causal overdetermination occurs when distinct events make symmetrical causal contributions to the occurrence of an effect. A criterion is called for that would allow us to distinguish cases where the overdetermining causes are on par with the effect from those where they are not. This study provides a partial answer to this question. To this end, we introduce a novel approach to characterize causal relations in terms of algebraic structures. Starting with a formal definition of symmetric redundancy couched in terms of the symmetries of the causal structure, we prove that, if such symmetries satisfy certain conditions, then the causal roles of overdetermining causes can be individuated in principle.</p>