Hello Valerie. Initially, I was wondering if this Hourihan/ O'Brien connection could be the same family.
I can't see a direct correlation with the dates, of both families.
There is always the possibility that there is a long, perhaps 2 links down the line, so who knows?
I also have links to Bandon (Barry, Collins, Sullivan), Timoleague (Madden), Rosscarberry (Dempsey),
Kinneigh (Murphy and Corcoran), Dunmanway (Hurley and Donovan) and general West Cork links, with Decoursey and O'Brien (specifics yet to be discovered).
Good luck with your research.
Regards from Cymru (Wales)