The invention provides a mechanism for allowing a transaction callback processing to be synchronized or to take effect prior to completion of a transaction or message. Additional Synchronization objects that will take part in the transaction can be registered on any server during the transaction's active phase. After the commit function is called, each Synchronization object is called during the transaction preprepare processing. A Synchronization object can register another Synchronized object, call a server not previously involved in the transaction, or involve a new XA resource in the transaction. The effect is to provide a circular pattern of request passing that allows additional resources to be added into the loop prior to commit.