Hi Mark,
Hope you are still interested to find your relatives.
I live in Canada and doing research on Rubinchik family history. Gussie Rubinchik was a cousin of my grandfather. I’ve already found huge branch of the family in US. Some siblings of your grandmother have survived the War. Just few weeks ago I’ve met with your grandmother’s niece in Israel and she gave me some photos of Gussie.
Looking forward to hearing from you.
Jane