At the moment you can define a build trigger "Build after other projects are built". If I define "jobA, jobB" as build triggers for jobX, jobX will be built after jobA finished and another time after jobB finished.
It would be great, if you could enhance this functionality, so that jobX waits until jobA AND jobB succesfully finished.
It can be implemented by more complex plugins like MultiJob, Build Pipeline, etc.