I first became aware of paired/pooled organ donation during my transplant work up. This was for the purpose of swapping kidneys around between donors and recipients making matches for living transplants much more likely.
I came across an article today where there has been a world's first non-identical organ swap. A lady (we'll call her "A") who had a mother on dialysis wanted to donate her kidney, but she was turned down as she was likely o suffer the same medical condition of her mum. Another lady (lady "b") wanted to donate part of her liver to her sister, but she was assessed as being unsuitable.
So lady "A" offered 50% of her liver to lady "b"'s sister. In return lady "b" would donate one of her kidneys to lady "a"'s mother. The article can be found here -
www.newscientist.com/article/2202261-my-liver-your-kidney-the-worlds-first-non-identical-organ-swap/This could potential open up many more matches for living transplants.