This may mean re-defining winning in such a way that all sides can have their needs met. Clarifying what each party wants, before they come to the table. This is the place where the common ground becomes clear. People can represent themselves. This dilutes the power of ideologues in favor of ordinary people.
Parties can get stuck trying to re-interpret each other s history.
Therefore, consensus may be that parties agree not to discuss certain hurtful parts of their history, at least until they can resolve their present difficulties and establish a certain level of trust. Although forgiveness must be an integral part of reconciliation, what form that takes in Sri Lanka will remain to be seen. Which method works best will only be determined on a case by case, nation by nation, basis.