Complex sentence: The nation also experienced difficulties in delimiting its borders with Argentina which wanted the whole Gran Chaco region: a demand which Paraguay could not accept, as this would entail surrendering more than half of its national territory.
Split into simpler sentences: The nation also experienced difficulties in delimiting its borders with Argentina. Argentina wanted the Gran Chaco placed completely under its flag: a demand which Paraguay could not accept, as this would entail surrendering more than half of its national territory.