  We discuss how to detect bipartite entanglement in a Dicke state of many
spin-1/2 particles. The particles are split into two subensembles, then
collective angular momentum measurements are carried out locally on the two
parts. First, we present a bipartite Einstein-Podolsky-Rosen (EPR) steering
criterion. Then, we present an entanglement condition that can detect bipartite
entanglement in such systems. We demonstrate the utility of the criterion by
applying it to a recent experiment given in K. Lange et al. [Science 360, 416
(2018)] realizing a Dicke state in a Bose- Einstein condensate of cold atoms,
in which the two subensembles were spatially separated from each other. Our
methods also work well if split spin-squeezed states are considered.
