Provided you export with the "Object Groups" option, then the script for Poser to split each group (of the currently selected prop) into a seperate props (named after the group) and then delete the source prop, is :-

scene = poser.Scene()
act = scene.CurrentActor()
geom = act.Geometry()
for grp in geom.Groups():
    g = scene.CreateGeomFromGroup(act, grp)
    p = scene.CreatePropFromGeom(g, grp)
scene.SelectActor(act)
scene.DeleteCurrentProp()

Which is much simpler than messing about with multiple files or writing a modified importer that handles the "o" lines.