Chord and MIDI data to one VSTi, Volume

I have a chord track, which sends data to instrument track with Kontakt 5 on it. Also I have a MIDI objects with the melody on this track too. I’d like to change the volume of chords and melody independently, but I can’t. The chord track doesn’t have a volume fader, and the instrument track fader controls VSTi volume, as expected. If I move the melody to a different MIDI track, it’s fader will control VSTi instrument volume, which also mean the same volume for melody and chords.
Could somebody help me with such problem?