My paternal grandmother, Esther Rebecca Trohn Rosenbloom (b. January 11, 1867, Mitau, Latvia), had a sister, Rosa Trohn Demby (b. March 1856, Russia), who married Morris Demby (b. May 1859, Russia) and had 4 children (Alexander, Rose, Ann and Lou). The Demby's came to New York by the late 1880's. Several of the Trohn's settled in New Rochelle. Most went to Staten Island or New Jersey. You may want to communicate with Nancy Camaur, firstname.lastname@example.org
, who knows a great deal more about these Demby's than I do.