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When did they emigrate? Can you tell from the census records? Naturalization records in Albany or at NARA in NYC?
Are they ever recorded as living really near each other, such as in the Schenectady town/city directories? Do they share the same occupations, etc. etc.
Do you have any evidence that they interacted with each other at all through out their lives? (At present, for a Gerrity brother-sister relationship I just have an odd 1870 census household record, and a 1933 obituary naming my own father as as pall-bearer for the 2 year old in that census! And now, a much older cousin going "Oh, yeah, my mother used to talk about them..." 50 years of visiting at New Years after leaving County Mayo reduced to that.)
And what years are we talking about here?
Also, have you tried to research "Sumin"? Could be Polish as well as any place in the Austro-Hungarian empire. Naturalization records will help with that a bit, likely. Ah, its POLISH: Wiki says "Sumin [ˈsumin] is a village in the administrative district of Gmina Wierzbinek, within Konin County, Greater Poland Voivodeship, in west-central Poland."
A parallel method of research is to skip directly back to Ye Old Sod. Its a lot lot lot easier to do that these days & there now must be some member of the Society who's already working the region. To my knowedge, the Society is NOT developing an in-house expert on Eastern Europe/Russia genealogy at present, but perhaps Research Service might know of a member who's working real hard. Again, review all possible links to genealogy online with Sumin, Poland, etc. Or repose this as a question David as the Online Genealogist. I could direct you to the relevant material on 6th floor Reference but neither you nor I are in Boston.
Hopes this helsp as least in a kick-start way.