You should use the viz.STEREO_RIGHT/viz.STEREO_LEFT modes for each computer. Here is some sample code:
Code:
viz.ipd(0.06)
viz.go(viz.FULLSCREEN)
viz.pushmask(viz.MASTER)
viz.stereo(viz.STEREO_RIGHT|viz.HMD)
viz.popmask()
viz.pushmask(viz.CLIENT1)
viz.stereo(viz.STEREO_LEFT|viz.HMD)
viz.popmask()