Same story on my side : to avoid the very long duty (several years) in the Czar' Army, the family legend is saying that 4 or 5 boys where registered (not sure about real adoption) under another name.  So this is clearly not a unique case

names : Winagrad, Rabinovitch, Bondar
location : Slonime (Russia), and Jassy (Bessarabia)

No clue about how to find the real names after such trick - by luck in looking at census with addresses, or missing children while looking at the years of birth (and only girls) etc... but really low low probability

David Choukroun
Paris, France
david.choukroun@...