At a local level, sure. Lots of legal systems regard certain types of mediation as binding and allow for something called "consent orders". Without some kind of overarching reciprocal agreement, though, (treaties and conventions are essentially just civil law agreements between nations) or legislative requirement (such as a full faith and credit law) there's not really any legal basis for enforcement across jurisdictions. As it stands, even when those requirements are met, there's no certainty that one state will domesticate the orders of another jurisdiction.
Sharia courts in Western countries would be an example of this. People can voluntarily subject themselves to Sharia justice, but the ability to enforce its provisions is extremely limited.