Have seen Ros Davies great Co Down website
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies/SURNAMES/R/Rea.htm she records 6 entries for John Rea of Killaney, you would need to see all of them She allows use of her collection but not for profit.
John/ James REA Killaney married Margaret Little in 1843 at Boardmills Presbyterian Church
children
James b. 12 Jan 1844
Mary b. 22 Apr 1845
Margaret b. 15 Mar 1847
ROBERT B. 28 Oct 1848
Prudence b. 28 May 1850
Eliza b. 10 Mar 1852
William John b. 28 May 1853
Essy Jane b. 21 Jul 1856
William Hamil Rea b. Dec 1858
William Hanna Rea b. 27 Nov 1860
George Hay Shanks Rea b. 10 Apr 1863 & bpt. Boardmills Presbyterian Church ; left for New Zealand PR
Ros Davies includes earlier Killaney Rea
Killaney she says is a small parish & townland of 298 acres; west of Saintfield;
another source of this period is Tithes Applotment Books 1823-1837
based upon the work of the Irish Genealogy Hub listing for each parish in Northern Ireland,
The relevant original books are in the Public Record Office of Northern Ireland (PRONI) Belfast
Rea, John-Townland: Ballyknockan Year: 1834-Saintfield -Down
Rea, John-Townland: Tullywesticonaught Year: 1834-Saintfield -Down
Rea, Joseph-Townland: Bresagh Year: 1834-Saintfield -Down
Rea, Robert-Townland: Tullywesticonaught Year: 1834-Saintfield -Down
Rea, Thomas-Townland: Tullywesticonaught Year: 1834-Saintfield -Down
Rea, Widow Townland: Tonaghmore Year: 1834-Saintfield –Down
to see how close they all were
http://freepages.genealogy.rootsweb.ancestry.com/~rosdavies/MAPS/SaintfieldKillaneyTownlands.htm