She intensified her illegal political activism after March 1938 which was when Fascist Austria was formally incorporated into an enlarged Nazi Germany following a largely unresisted military invasion from the north-west. Margarete Jost became a member of the regional "Provinzkommission". From 1938 she was working as a contact between locals party activists and senior party officials. She became the party contact for the "Südbahnstrecke" - the part of Vienna surrounding the Südbahnhof railway terminus. On the one side this involved communicating instructions from the party regional leadership to activists living "underground" (their place of residence not registered with the city authorities): on the other hand she was responsible for passing to the leadership reports of the "illegal work" undertaken by activists in this part of Vienna. In July 1940 the authorities arrested forty members of the organisation, but even after this sources indicate that there were still around fifty communist activists in the district defined, for the purposes of party organisation, by the suburb of Baden and the surrounding district ("Bezirk Baden und Umgebung"). Jost administered cash contributions and the application of the funds to support comrades who had been arrested and the families left destitute by those arrests.