Most efficient way of setting up a project Pydev PYTHONPATH in Eclipse (Helios)?

I want to add all folders in my Pydev project to PYTHONPATH so that I can reap the benefits of easily seeing unused imports etc. To do this I seemingly have to add all folders manually including the subfolders, one by one. Is there any way to add them all at once (recursively) or am I doing this completely wrong?

Now I right click the project in the Navigator and select Preferences. From there I go to Pydev-PYTHONPATH and finally I can add the folders.