  The interplay between the LHC and the $e^+ e^-$ International Linear Collider
(ILC) with $\sqrt{s}=500$ GeV might be crucial for the discrimination between
the minimal and next-to-minimal supersymmetric standard model. We present an
NMSSM scenario, where the light neutralinos have a significant singlino
component, that cannot be distinguished from the MSSM by cross sections and
mass measurements. Mass and mixing state predictions for the heavier
neutralinos from the ILC analysis at different energy stages and comparison
with observation at the LHC, lead to clear identification of the particle
character and identify the underlying supersymmetric model.
