Hi Dubnut,
The James Maher you referred to is my GGG Grandfather, so I guess we're distantly related! I was aware that James had a contemporary named John, but I wasn't sure how they were related. In fact, I know nothing about John apart from where he is buried (Deansgrange). However, I'd be delighted to share the bits I know about my side of the Mahers from later on in the 19th century, as well as little bits I've picked up about the Tallants and Stapletons.
Best wishes cousin,
Stephen
P.M. to follow