I have this hierarchy on my project:

  /
    projectA/
      build/
        jamfile
      win/
        a.ccp
      mac/
        a.cpp
      some.cpp

    projectB/
      build/
        jamfile
      win/
        b.cpp
      mac/
        b.cpp
      some.cpp

    jamroot

I'd like to know, how to write a rule in my jamroot that gets the right specific platform sources ? And I don't want to call this rule in every jamfile.

Thank you.