I am just beginning my research and would love any Rosenstein information you have already collected.
My grandmother was born Frania Rosenstein.She married into the Mitzenmacher or Mitzmacher family after liberation of Bergen-Belsen in Germany.I know that she had a sister who was killed in the camps and subsequently took in her sisters one surviving daughter, Batsheva.
I don't know the names of her parents, but someone once told me her mother was Ida Rosenstein.Not sure how accurate that source is.
She did have two brothers... Shimone, who lived and died in Arizona, and David who married Sala (Sally) and lived in New York.They had two daughters, Etta and Selena.
Email me at firstname.lastname@example.org if you can help!