nope .. not possible as far as i remember.
(that said, id need to go double check the generator code, see if there was a special case defined)
the underlying issue is...
any reference in a polyphonic voice is considered to be 'per voice', there is no way to differentiate common elements like the reference to the parent.
there is no way to go from the root, its relative
(*) unfortunately, given 2.0.0 is just released, id not want to dig into the 1.0 code now.. as id prefer to concentrate on 2.0
(note: 2.0.0 has same 'issue')