Conflicting interest

Today in class Mary Parker Follet's idea of confronting interest was discussed.According to it the best way of dealing with confronting interests is to integrate them together.But in the case of diametrically oppposing conflicting interest that does not seem very plausible. How can two conflicting interests , be integrated for the sake of co-ordinated action in pursuit of one common purpose.People join an action to fulfill their own interest.If that gets compromised, to integrate its complete opposite ,why will the concerned parties go forward.