Hi Barbara:
Historic Graves website has two graveyards associated with Gortnahoe online at the following links:
https://historicgraves.com/graveyard/gortnahoe-new-cemetery/ts-ghnc
https://historicgraves.com/graveyard/gortnahoe/ts-gtnh
It is worth going through those links to see if you can find any headstone associated with the family. If you cannot, you will note that the transcriptions and recording of the graveyards was done by the Slieveardagh Barony Historical Group and they have a link with other graveyards that they have done. It might be worth either contacting them directly or looking through some of the nearby graveyards.
https://historicgraves.com/project/slieveardagh-barony-historic-graveyard-survey
I will also contact a few volunteers to see if they can add any further input to your query.
Many thanks for your interest in Ireland Reaching Out.
Kind regards,
Jane