I am searching for information on my father's family. My 4 great-grandparents were Polish. All immigrated between 1903-1907 through Ellis Island. I can't find the immigration record of one great-grandparent. Other than the town names and surnames, I don't know anything else about where my grandparents are from and I don't know how to proceed with the research. I do think all 4 were Roman Catholic which might help with records searchers.