Maven flex project using source directory from seperate module with new artifactId

Question

Finding it difficult to express myself easily around this issue so thought best to start with a context section:

Context:

I have a Flex based application (a rather complex system) that can be compiled using "conditional compilation" into various use cases eg:

Compilation One = portalProjectUserOne Compilation two = portalProjectUserTwo

Whether using conditional compilation is a sound idea is a completly different argument and therefore lets assume one is forced down this road, I then however decide to create a project for each of my desired compilations:

portalProjectUserOne -branches -tags -trunk -src -pom

portalProjectUserTwo -branches -tags -trunk -src -{NEEDS TO USE PROJECT ONES SOURCE}

As I do not want to break the ever rigid laws of programming and not duplicate anything I need a way of accessing the source of project ONE and using the source to do a CUSTOM compilation.

Things I have tried:

1. I tried using relative paths (../../portalProjectUserOne/trunk/src/etc...) with successful compilation but when it came time to release a final product to the nexus repo it had a few issues with reaching out the project structure, that and it felt a bit dirty really.
2. I attempted to use the "maven-dependency-plugin" to try and copy the sources from the first project, maybe this a pure lack of understanding on my part but I can not get my head around how you generate your classes in one project and access them from another.

This is my first question on stackoverflow and if I have been far to broad please let me know and I shall update with more extensive examples if required.

Thanks for listening/reading/being a coder.