The key to modelling multi-party cases is to recognise that in legal terms, they represent a series of separate cases heard at the same time. The number of cases is (number of defendants *2)-1. For case provisioning typically only I combined model is necessary, but potentially the range of models that might be required or could be made is number of defendants +1.
Shake and Settle!
Use Shake and SettleIndex together to find the optimum settlement quickly