selMappings.add(verts[j]);
if (j == verts.length - 1) {
nextBits.set(sels.size());
sels.add(sel);
} else
sels.add(sel.fullClone(1));
}
// turn off unioning if a given independent mapping requires
// multiple selects, or if we're using FROM selects
if (verts.length > 1 || sel.getFromSelect() != null)