Load MIDI mapping preserving the existing mapping

renoise.song():load_midi_mappings(filename) seems that it only allows you to load a MIDI mapping file but destroying all the mapping already established in the song.

Is there any way to load an XRNM file without losing the mapping already established in the song from a tool?

Another question. Is there any way to load two or more separate XRNM files at the same time without deleting each other?

As it is now, it is only possible to load an XRNM file when starting an empty song. If you already have a mapping established in your song, for example, in the middle of the project, it will destroy it. This is a bit limited. Any help is appreciated. (join two or more XRNM files through a function I do not see it very reasonable either).

-- Load/save all global MIDI mappings in the song into a XRNM file. 
-- Returns true when loading/saving succeeded, else false and the error_message.
  -> [boolean, error_message or nil]
  -> [boolean, error_message or nil]

-- clear all MIDI mappings in the song

By the way. I think there is a problem with the XRNM extension to load it with Renoise. In Windows 10, if you double-click to load the file from the Windows 10 disk browser, it will not load it correctly. Apparently, you can only do it from the MIDI Mapping window.