Budapest was liberated in January and February 1945. Grossmann became a member of the American Jewish Joint Distribution Committee and a co-chairman of the Hungarian Zionist Association. He became a director of the Budapest "Eretz-Israel" office. He also engaged with the reintegration of large numbers of returning refugees through the creation of 31 agricultural co-operatives and 50 commercial co-operatives. Sadly, however, the defeat of National Socialism had not put an end to race based discrimination. The 1940s were a decade of on-going ethnic cleansing across much of central Europe. The problem now was not that Grossmann was Jewish, but that he was a mother-tongue German speaker. During 1949 he left Hungary.