Genealogy / Looking for Relatives - Surname Gelber [NEW]

I'm trying to track down some possible relatives. The surname is Gelber and the relatives names are Alexander, Leo (Aryeh Leib) Meir, Betta, or Nachman, or that has a parent with the name Esther from around the 1940s?

Leo (Aryeh Leib) is my great-grandfather (my grandma's father's family)

I know this isn't much to go off of but my family don't have a lot of information about his relatives.
I know the mother, siblings, and that they lived in Poland (town unknown). Also that Leo (Aryeh Leib) was taken into the Polish army against the Russians.