I think there is a conceptual mistake on MIDI I/O Mode set to Hybrid:
• Normally, MIDI data is sent from the channel that is set in the MIDI I/O Channel parameter.
• For Part with Keyboard Control Switch set to Off, MIDI data are sent just if part is selected.

According to me: MIDI data have to be sent in any case for the common channel and for all the parts, even if Keyboard Control Switch is set to Off.
In this way, setting LOCAL OFF and using an easy external filtering and routing, you can use both an external master keyboard or use the MODX as mast.
You could play the whole complete performance and/or the single part form external Mater or from the MODX itself.🙁

I know Camelot could do the same, but:
• An Apple device is needed
• An external SW has to used
• An extra configuration and settings of performances are needed

Do you think would it be ever implemented?

Thanks
Domenico