You can get a handle to sub-parts of the object and then move them:
Code:
import viz
import vizact
viz.go()
viz.move([0,0,-7])
dojo = viz.addChild('dojo.osgb')
lamps = dojo.getChild('wall lamps-GEODE')
moveRight = vizact.move(1,0,0,time=5)
moveLeft = vizact.move(-1,0,0,time=5)
move = vizact.sequence([moveRight,moveLeft],viz.FOREVER)
lamps.runAction(move)