Maybe you can give an example.
Say you have a water dispute between two geographically close regions. Group A doesn't have enough water to give to its people and the only economically viable source is group B.
Group B has plenty of water and because of that, they also have plenty of food and are basically self sufficient.
Group C also has water but they live so far away that acquiring that water becomes financially impossible for group A.
In a free world the clear solution is to have people move from group A to group B and C. Either move the resources to the people or move the people to the resources. Without the artificial boundaries created by governments we would not have the problem you are describing.
And what if the people that live by the resources do not want to give up the resource?