Hi
My name is Roisin I don't know if we are talking about the same people but my great grandfather is Peter McGahen, but looking back on some documents they had also spelt it McGahey. We found them living in Belfast city center on Wilson's court in 1910 census.
Peter McGahey was my great great grandfather his son Peter is my great grandfather, he married in Belfast to Mary Dawson and died in Belfast on 1947, one of his sons Joseph McGahen is my grandfather who's son is Michael McGahen my dad who lives in Ardoyne, Belfast. My dad has 3 sisters Hannah, Eileen and May and 1 brother John, who all live in Belfast. Unfortunately my granda Joseph died in 1989 when I was 13yrs and my granny died in 2014 with 5 kids, 17 grandkids and 18 great grandkids with a few more added on since then.
One of Peter's sisters Margaret married a soldier in Belfast and emigrated to America in the 1920's. I just found and got contact with her grand children within the last 5 years they live in LA, California.