By default, QuadraVox voices A & C pan to the left, and voices B & D pan to the right. Beyond the +/- 2 octave Pitch ranges, each voice can also be set to OFF.
With two instances of QuadraVox in Parallel routing, Q/V1 Pitch Mix fully CW, and Q/V2 Pitch Mix fully CCW, voice B will route to Out 2, and voice C will route to Out 1. Set voices A & C to OFF.
If you only need the two voices, a similar Diatonic setup in Parallel will get you there. You can (optionally) add Delay time & Feedback to each voice, with some unique routing effects. In this case it would be voice A to Out 1 and Voice B to Out 2, with opposing Pitch Mix settings.