Simultaneous opposite changes on two tracks?

Hi - Maybe this isn’t the best way to do this, but I have a three-part harmony that I’d like to have the focus of attention change over time from one part to another. What I’ve been doing is fading volume and/or EQ up on one track, then going another part are fading the same parameter down.

This has been a two step process, but I’m wondering if there is a way to have two editors open at one time and while making a change in one vocal part, the opposite change takes place in the other part?

Thanks much for any thoughts!

don’t know of an automatic two-editor system but i guess IF it were a two part harmony and IF you only wanted to invert volume automation between the two you could combine them into stereo and play with the pan - then just put them on a mono track.

If you find a solution let me have it!