The transplants are carried out at once to stop donors backing out
US doctors have carried out what is believed to be the world's first simultaneous six-way kidney transplant.
Six recipients received organs from six donors in operations at the Johns Hopkins Hospital in Maryland.
The procedure was made possible after an altruistic donor - neither a friend nor relative of any of the six patients - was found to match one of them.
Five patients had a willing donor whose kidney was incompatible with theirs, but it did match another in the group.
This meant that suddenly, there were six people who could receive an organ.
The operations were carried out simultaneously to make sure no-one backed out after their loved one had received a kidney.
"All 12 are doing great, the six kidneys are working well," said Dr Robert Montgomery, director of the transplant centre at the Johns Hopkins hospital.
The hospital has been one of the pioneers of this system which matches up several groups of people at one time.
It aims to circumvent the problem of altruistic donors ending up in arbitrary allocation systems where only a single patient's needs are served.
The hospital has been carrying out these simultaneous transplants for three years: in 2005, the first triple procedure was performed, a year later, the first five-way.
Nearly 100 medical professionals were needed to make the complex series of transplants possible, from immunogeneticists to hinder rejection to psychologists.
If all goes to plan, each patient can expect their new kidney to last for as long as 20 years.
Recipient Jeanne Heise, whose husband donated to another patient, said more people should know about the system.
"The waiting list for a kidney is very long and too many people die while waiting," she said. "With this group procedure, more and more people can beat kidney disease and live long productive lives."
The UK has so far carried out only two-way transplants, with the most recent - the third - just this week. The prospect of three-way transplants is currently being examined.
A spokesman for UK transplant welcomed the news that the US had achieved a six-way procedure, but said the organisation and logistics required for such a process meant it was still a "very long way off" for the UK.