Duplicate Java Files

We have a project:

/vobs/psip/

As part of this project, we have product specific code, and common code:

/vobs/psip/src/product1/...
/vobs/psip/src/product2/...

And some common code.

/vobs/psip/src/common/...

And of course we have unit tests

/vobs/psip/utest_shadow/product1/...
/vobs/psip/utest_shadow/product2/...
/vobs/psip/utest_shadow/common/...

The problem is how do we express this hierarchy in IDEA proejcts. (our makefiles build this just fine).

Ideally, I would have 3 modules. A common module, and 2 product specific modules, each of which depend on the common module.

Unfortunately, two modules cannot share the same content root.

Alternatively, I can create content roots that are much deeper.

Module Common:
Content1: /vobs/psip/src/common/...
src: ./
Content2: /vobs/psip/utest_shadow/common/...
unit test: ./

But this seems a bit off. When I do this, everything works fine, except when I do a ctrl-n, everything in the common module is comming up duplicate.

If I remove the dependency from program1 to common, I still get 2 entries, but one of them is a class file, and not a source file (even though I have exclude output path turned on for the common module).

I'm thinking I'm doing something wrong (i.e. it isn't a bug, just a dumb user problem), but I can't quite put my finger on it. Anyone else out there solved this?

Thanks,
Mike