  A full treatment for the scattering of an arbitrary number of bosons through
a Bell multiport beam splitter is presented that includes all possible output
arrangements. Due to exchange symmetry, the event statistics differs
dramatically from the classical case in which the realization probabilities are
given by combinatorics. A law for the suppression of output configurations is
derived and shown to apply for the majority of all possible arrangements. Such
multiparticle interference effects dominate at the level of single transition
amplitudes, while a generic bosonic signature can be observed when the average
number of occupied ports or the typical number of particles per port is
considered. The results allow to classify in a common approach several recent
experiments and theoretical studies and disclose many accessible quantum
statistical effects involving many particles.
