These rules are adopted by the Supreme Court of New Hampshire pursuant to the authority established in Part II, Article 73-A of the New Hampshire Constitution. In exceptional circumstances, when the court finds that the application of these rules to cases pending as of the effective date would not be feasible or would work an injustice, the court may exempt such cases from the application of these rules or from a particular rule.
N.h. R. Super. Ct., Preamble