Samuel Gregory m. Susan Parrish, daughter of Daniel Parrish. Samuel's family was originally from Delaware Co. NY, founded the Colchester area along with Daniel Parrish, who was the first school teacher and built the first schoolhouse after the Rev. War. Another of his daughters married Abraham Sprague, another founding family.
I don't have a list of Gregory's siblings, but there is a book about Delaware County online in the Making of America Books project. The database is free and the pages are scanned. It takes some time but it's well worth the effort.