  We consider two ensembles of qubit dissipating into two overlapping
environments, that is with a certain number of qubit in common that dissipate
into both environments. We then study the dynamics of bipartite entanglement
between the two ensembles by excluding the common qubit. To get analytical
solutions for an arbitrary number of qubit we consider initial states with a
single excitation and show that the largest amount of entanglement can be
created when excitations are initially located among side (non common) qubit.
Moreover, the stationary entanglement exhibits a monotonic (resp.
non-monotonic) scaling versus the number of common (resp. side) qubit.
