The Super Separator Spectrometer (S3) is a device to be designed for experiments with the very high intensity stable beams of LINAG, the superconducting linear accelerator of GANIL, which will be built in the framework of SPIRAL2. These beams, which will provide in a first phase of SPIRAL2 ions with A/q = 3, can reach intensities exceeding 100 pµA for lighter ones - A<40-50 depending on the final choice of the ECR (Electron Cyclotron Resonance) ion source. These unprecedented intensities open new opportunities in several physics domains, e.g.: super-heavy and very-heavy nuclei, spectroscopy at and beyond the dripline, multi-nucleon transfer and deep-inelastic reactions, isomers, ground state properties and molecular resonances. An international collaboration has been formed for proposing physics experiments and developing technical solutions for this new instrument. All of the experiments mentioned have the common feature of requiring the separation of very rare events from intense backgrounds. Hence, the present study is aimed at finding an appropriate technical solution for a pre-separator stage of S3. The layout being considered is a sequence of four Wien-filter stages arranged as a chicane or dog-leg. The Wien filters are tuned to transport all charge states of the primary beam undeflected to an intermediate image between the second and third Wien filters, the mid-point of the mirror symmetric layout. There is a beam stop at this location and the lower-velocity fusion products are deflected and pass around the beam stop. The overall system is fully achromatic so that the full velocity range and all charge states of the fusion products are imaged at the exit of the pre-separator. Presently the degree of beam rejection and the performance vs. acceptance of this concept are being studied.