We investigate the "teleportation" of a quantum state using three-particle
entanglement to either one of two receivers in such a way that, generally,
either one of the two, but only one, ran fully reconstruct the quantum stat
e conditioned on the measurement outcome of the other. We furthermore delin
eate the similarities between this process and a quantum nondemolition meas
urement. [S1050-2947(98)08812-X].