You didn't say what country they ended up in? If it's the USA, you can send for copies of their immigration papers, which may help.
I know this is a lot earlier, but on Ellis Island data base, there is one Diczun, Anton, arrived 4/11/1910, from a Pjoter, town looks like Paldez, Polsdoz, or Poladsz, in the Kowno district. I think the town is actually Palaidziai in the Birzai region, which would of been part of the larger area known as Kowno or Kovno.