In switch-reference (SR) constructions in Mparntwe Arrernte, if two subjects are in a part-whole relation, same-subject (SS) marking is obligatory and different-subject (DS) marking is ungrammatical. This means that Mparntwe Arrernte treats subjects in a part-whole relation the same way as coreferential subjects. This does not extend to subjects in other types of possessive relations, e.g. kinship or inalienable relations. The possessed subject need not be overtly coded for possession to license SS-marking, even though possessive phrases outside of the context of SR do require overt coding of possession.
Wilkins, David. 1988. Switch-Reference in Mparntwe Arrernte (Aranda), in Peter Austin (ed.), Complex sentence constructions in Australian languages, 141-176. Amsterdam: John Benjamins.