  We derive a many-particle inseparability criterion for mixed states using the
relation between single-mode and many-particle nonclassicalities. It works very
well not only in the vicinity of the Dicke states, but also for the
superposition of them: superradiant ground state of finite/infinite number of
particles and time evolution of single-photon superradiance. We also obtain a
criterion for ensemble-field entanglement which works fine for such kind of
states. Even though the collective excitations of the many-particle system is
sub-Poissonian --which results in entanglement-- the wave function displays
bunching.
