Compile as two separate libraries.
it is possible to specify a library to be merged into another library so you can produce a single library to satisfy whatever reasoning you have for doing so.
specify the ‘child’ library in OBJLIBFILES= in your SOURCES for the parent. The libraries will be included into the parent library.
You might need to pay attention to BUILD_PRODUCES and BUILD_CONSUMES hints as well.
Good Luck,
Dave Cattley