Complex sentence: Regarding requiring Government intervention in investment decisions, I do not think that "X-Y relations" is limited to "X-Y Governmental relations", but I do think that direct foreign investment in a country's biggest port operation is a bilateral interaction.
Split into simpler sentences: Regarding requiring Government intervention in investment decisions, I do not think that "X-Y relations" is limited to "X-Y Governmental relations". In my opinion direct foreign investment in a country's biggest port operation is a bilateral interaction.