Hi David,
Path is no longer supported. However, my understanding is that you are trying to bring models into Path as part of a process to eventually import the models to ST-Sim. In ST-Sim there are no such limits.
In VDDT and Path there was a limit on 3 transition groups per project, however the import process you are going through in Path merges all of the projects in a VDDT library into a single project in Path hence you are running into this violation. There is no simple solution to the problem although there are definitely workarounds that you could do to get your VDDT models into ST-Sim by working directly with the databases. If you are interested in help with this please check out our support page: http://www.apexrms.com/support/
Regards,
Leonardo