[boost] [build] b2 headers don't work for sublibs

Hi, I'm trying to move some headers of Boost.MPL to a sublib Boost.MPL.Core. I've reorganized the repository as follows: libs mpl book core include boost <- here and below are core headers test index.html doc example include boost <- here and below are the rest headers meta preprocessed test .git .gitattributes README.md index.html sublibs The problem is when I run 'b2 headers' the command creates a symlink boost/mpl pointing to libs/mpl/include/boost/mpl, which leaves out all headers from libs/mpl/core/include/boost/mpl. How do I instruct Boost.Build to create links to the core headers?