It does fit how I proposed it (and consequently implemented it).  I decided to group all library headers together, see below for the excerpt from the original post with two lines added for clarity.

    ...
    #include "json/a_file.h"
    #include <library1.h>
    #include <library2.h>
    #include "namedLibrary.h"       // Added

    #ifdef SOMETHING2
    #include <aLibraryStartingWithA.h>       // Added
    #include <library3.h>
    #endif 
    ...