MIDI assignment: two staffs to same channel

[Giampaolo Orrigo]

Hello list,

is there a way to assign two staves to the same MIDI channel when creating MIDI in Lilypond?

I am trying to redirect frescobaldi MIDI output to the organ sim sw Hauptwerk and while I have been finally successful, still the fact that the two organ staves are assigned to two different channels make the msuic only partially playable.

Thanks,

Giampaolo