Robert Gray living in Belfast 1859.

You found evidence for me ,of Robert Gray Agricultural Implement maker in the Belfast street directory 1858/59. Robert was the father of Jessie Gray who married Samuel McConnell in 1859 Belfast. The Grays were from Kirkoswald in Scotland. When I look at the street directory I can also see James, John and David Gray in the same listing. These 3 were also the names of the brothers of Robert Gray and also all 3 were the names of his sons. Is there anyway of finding out if the whole Gray family had moved to Belfast from Scotland back in that period? Or is it maybe just a coincidence? Many thanks Linda Tarsa