Sonja Reusser? Yes. She never rode for a UCI team, but Bike-Import.ch did have former/later pros like Nicole Hanselmann and Pascale Schnider in its roster during her time with them.
Despite them both being from the Bern region, it doesn't seem like Sonja and Marlen are related. Sonja is however the sister of Walter Reusser, who's the director of alpine skiing in the Swiss federation. But I mainly picked her because I found out she was competing in lower level ski mountaineering.