I'm not sure if there is a connection. In my tree I have a Hans Gray born about 1730 and died 1807. He may have been married to an Elizabeth. The Muster Roll of 1631 held in Bangor listed two John Grays, two James's and a Gilbert. These were likely those who came over from Scotland in the previous 30 years. Their descendants settled in various areas around Bangor, Newtownards and Comber but we have existing documents to sort them out. My Grays likely went directly to Gransha near Bangor when they arrived and stayed there. So few early records survive or were never made that I don't know how you can connect the Grays together. Some would likely have been related in Scotland.