You can convert .dxf files to .dwg and insert them as external references into one main drawing. After that using binding they can be merged into main drawing. See OdDbXrefMan::bind() - XRefMan.h
You can convert .dxf files to .dwg and insert them as external references into one main drawing. After that using binding they can be merged into main drawing. See OdDbXrefMan::bind() - XRefMan.h