Editing 2 MIDI Envelopes into 1

does anyone know how to edit 2 MIDI envelopes into 1?
basically I have cymbals into metal foundry and shells as perfect drums (as shown in the attachment) and want to be able to edit drum grooves easily so would like to open both midi envelopes as 1 and manually draw in notes in the piano roll

Thanks in advance


Select both MIDI Parts and open the Key Editor.

idk why i didnt already try that lol