Looking for the Ireland Connection for Buchanan S

One of the family lines I am researching is William and Mary Ward Buchanan.

I have William (1756-1830) and coming from Blairlush, Tyrone, Donegal, Ireland.

And Mary Ward Buchanan (1767-1802) from Donegal, Ireland.

My line is from there daughter, Elizabeth Buchanan (1790-1858)who married John Graham and their son George W Buchanan (1793-1865) who married Hannah White.

I'm looking for any one who is connected to them and can help out with the line going back from William and Mary.