MusicTechHelpGuy shows how to layer multiple software instruments in Logic Pro so they respond to one shared MIDI part, using a Summing Stack instead of duplicating MIDI across tracks.
Two Alchemy patches and an ES2 get grouped into a stack, then a single chord recording drives all three instruments at once. Quantizing to a whole note and forcing Legato cleans up the performance across every layer simultaneously.
Each instrument inside the stack can still be mixed on its own: individual panning, EQ carving on a bright pad, and a MIDI Transposer dropping an arpeggiator down an octave to work as a bassline.
Effects like ChromaGlow can also be applied at the stack level to glue the whole layered sound together.