REA of Maharynock Hill (Mill?)

Short story: My grandfather immigrated from Belfast to Canada with his parents in 1910. With that starting point, and using online birth and marriage records we collected enough information to merit a trip to Belfast. The central library newspaper microfiche collection of the Belfast Telegraph yielded my great great grandfather's obituary, with a notice that he would be buried in the family plot in Saintfield. It took a while, but we found his grave and a "new" monument from 1906, in the Saintfield Church of Ireland cemetery. The monument was erected by my gggrandfather Samuel Rea, and his son David John Rea, in memory of several of their cousins. Moreover, in the very same plot and within a low iron fence, we found a very old horizontal slab monument to David Rea of Maharynock Mill. This is precisely the individual referred to by Dr William Roulston in his paper "Reconstructing an eighteenth-century Ulster family: the Reas of Magheraknock and Killeen, County Down." In this double discovery have found what is likely to be the earliest documented Irish family ancestor I could hope for!

But!

We have a missing link between the old and new: There is about 80 years between the last of this Maharynock Mill (Hill?) family and my gggrandfather buried in the same plot in 1906.

The old monument says:

"Here lyeth ye body of David Rea of Maharynock Hill, who departed
this life ye 16 of March 1754, aged 82 years, and also his son Hugh
Rea of said place, who departed this life ye 2 of June 1759, aged 42
years, likewise the body of his son David Rea, who departed this life
January 3d 1770, aged 13 years, also ye rimains of Elizabeth Rea otherwise Jackson, wife to ye above Hugh Rea, who died October ye 8th 1779, aged 62 years, here lyeth ye body of Cathrin Rea otherwise Barnett, wife of Matthew Rea, who departed ys life ye 2d of January
1781, aged 68 years."

Is anyone in this group descended from David Rea of Maharynock Hill (Saintfield, Co Down) or have any information on his descendants that would help connect the two ends together?

Thank you and best of luck in your own search!