In this paper the author continues his preceding researches on matroidal hyperstructures. A new class of hypergroups is introduced, called M_λ. These hypergroups are generated by the action of a group on a set. Necessary and sufficient conditions are given for an M_λ-hypergroupoid to be matroidal. The case of matroidal M_λ-hypergroups coming from the natural action of the multiplicative group of a field K on a K-vector space is studied.
