I wonder if these could be index entries for the wills of John Gregg died in 1724 and Richard Gregg in 1741 in Ardmore
W Phillimore (ed).Indexes to Irish Wills, Volume 2 1910,
Cloyne
John Grigg 1724 and Richard Grigg 1741 Ardprior https://www.ancestry.com/sharing/28531010?h=5d690e There is also a 1670 for a John Grigg of Dromore
W Phillimore (ed). Indexes to Irish Wills, volume II 1910 reprint 1970
I don't know Ireland very well but google says Ardprior is about 19 km from Ardmore.
Is Grigg, Gregg? Or is it just coincidence?
Couldn't find a William for 1672
EDIT . This later index of will abstracts in the genealogical office Dublin, 1949 ( p 255) includes the same three Griggs but John Grigg 1670 is listed as of Ardmore (not Dromore). These abstracts presumably still survive.