How to extend application processing?

[Scicomath]

I already read the document about "How to extend package processing" here: https://bloomberg.github.io/bde-tools/cmake/customization.html#how-to-extend-package-processing

But it doesn't say how to extend application processing.
For example, I have a repo like this:

• repo
  • applications
    • m_xxxxx
      • package
        • m_xxxxx.cmake
        • m_xxxxx.mem
      • m_xxxxx.m.cpp

Now, m_xxxxx.m.cpp depends some other third-party libraries, how can I successfully build the repo?

For normal package, I aleady know how to do it by reading "How to extend package processing". But this doesn't work for application component.