We have fabricated and tested two stacks of strongly coupled long Josephson junctions with access to the intermediate electrode so that they can be independently biased. In these samples, we find four families of voltage-locked states in zero external magnetic field. One of these families is identified with the zero field steps already observed and interpreted in the case of weaker coupling; the others appear to be new phenomena. The voltage spacing of one of them suggests the necessity of a refinement of the current model to obtain a full description of the dynamical states in stacked junctions. © 1998 American Institute of Physics.