When the joining job executes, it does not have access to the caller's
environment. This makes it "impossible", for example, to have a parameterized
job trigger a joining job and have the latter use user input (work arounds could
involve writing and reading to file on a shared drive).

The Parameterized Trigger Plugin allows calling subjobs while passing in the
caller's arguments. The same could most probably be implemented when calling the
joining job.