Dear Mr. Fadeev,
Thank you for posting your question on History Hub!
We searched the National Archives Catalog and located the series Records Relating to the Activities of the Einwandererzentralstelle (EWZ), 1946-1994 (Microfilm Publication A3342) in the National Archives Collection of Foreign Records Seized (Record Group 242) that includes the subseries EWZ50. Roll J051 is part of that subseries, and, based on the information you provided, the file including information about the Zwetzich family should begin on frame 1536 of that microfilm roll. These records have not been digitized. For additional information about and access to these microfilmed records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at firstname.lastname@example.org.
More information about the Captured German Records may be located on the National Archives website.
Due to the COVID-19 pandemic and pursuant to guidance received from the Office of Management and Budget (OMB), NARA has adjusted its normal operations to balance the need of completing its mission-critical work while also adhering to the recommended social distancing for the safety of NARA staff. As a result of this re-prioritization of activities, you may experience a delay in receiving an initial acknowledgement as well as a substantive response to your reference request from RDT2. We apologize for this inconvenience and appreciate your understanding and patience.
We hope this is helpful. Best of luck with your family research!