I often get packages from Germany that are sent with DHL with final delivery through POST Luxembourg.
The DHL tracking gives as its final step the following:
"The shipment will be transported to the destination country/destination area and, from there, handed over to the delivery organization. (Homepage / online shipment tracking: http://www.trackandtrace.lu/homepage.htm?locale=en_GB)"
I can then continue tracking via trackandtrace.lu with the same package number.
The final text returned by DHL is quite specific. It would be nice if this text would be detected and if a partial delivery would then be added automatically.
Let me know if you need further information regarding this suggestion.