This article is part of a special issue on Intelligent Agents in Healthcare. The shortage of human organs for transplantation is a serious problem, yet the current organ selection and assignment processes discard many organs deemed nonviable for transplantation. However, these processes ignore that medical specialists might disagree as to whether an organ is viable. A novel organ selection process lets transplant physicians, who might be geographically dispersed, deliberate over an organ's viability. This argument-based deliberation is formalized in a multiagent system called Carrel+, which requires the deliberation to adhere to formal rigorous standards acknowledging the domain's safety-critical nature.