The other way of doing it would be to create your animation. Then apply the talk designer to one figure save out the motions for the effected parts (mouth, eyes, etc) as a multi-frame pose, reset the animation and talk design the other figure then reapply the saved motions back to the first figure.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13