I believe that I may have some history on the Jablonski's who resided in the South Chicago area. From what I can tell by your dates listed above, it seems as perhaps your grandfather, Frank Jablonski, and my great-grandfather John Jablonski may be related as brothers. I don't have any information on my great-grandfather's sibilings. My great-grandfather (John Jablonski) lived in the South Chicago area and raised his family with his first wife, (my great-grandmother Apolonia), who passed away suddenly when my granfather and his sisters were very young children. My great-grandfather then remarried a women who also had children of her own. My grandfather, Walter Jablonski, married my grandmother Genevieve Szczucki, and they also lived in South Chicago (on Houston Ave, right next door to Powers Funeral Home.) and raised four boys, one of which is my father and is the only surviving of his three brothers. My grandfather Walter, was born in 1900, worked at one of the local steel mills and passed away in 1983. All of my Jablonski family relatives are buried at Holy Cross Cemetary, in Calumet City. My family also has a family plot located a little down the road in the cemetary from where most of the Jablonski's are burried. I have an old photo of my great-grandfather given to me by my father. He was a thin, man with dark brown hair, and had a very long, curly mustache. My great-grandfather passed away in his 50's. I would be happy to share additional information with you if you think this may be the correct family.