Dora Katz – A Research by Ellen Trencher

I know this is a long shot but worth a try. 

I recently discovered that my grandmother Celia Katz (1895-1981) and her sister Pauline (1892-1972) had a sister Dora which I discovered through correspondence from 1936.  Celia and Pauline, who are mentioned in the letter below, emigrated to the USA. Dora, their parents, as well as people mentioned in the letter below, did not. 
They were born to Solomon/Zalman Katz and Rose Fuchs in Chudey, about 10 miles from Czernowitz. 
For years I have been trying to obtain info about the family that remained behind. In addition I have been unable to locate any birth records for Celia and Pauline. 
Any guidance, help would be greatly appreciated.  
Thanks so much.