I have been entering transcriptions from a Cemetery in Fall River, MA. There are a large number of people buried here from Berehaven. I will venture a guess that they came to Fall River, MA after the copper mine closed. I've been uploading spreadsheets to Find-a-grave. That site only lets me enter Cork, not the town of Berehaven, so you can't search there.
Berehaven used to be a parish, but it is not listed as one now, so I can't connect to a specific message board for that community.
As they aren't my family, I'm not going to enter all of them, but I was looking for a good place to post this link. It's the transcription of all the persons in this cemetery. You can search by name.
The Cemetery of St. John's was established in 1850. Most of the burial record 1850-1891 are missing.
I do have relatives in this cemetery. And I do have relatives from Cork. But I don't know much about John Casey (common name) yet. I look forward to connecting with the Cork community sometime.