Create a new rule called, “Groundhogs Remember”:

There exists a wiki document called “Parallel Ruleset” which may not be modified except as specified by this rule. Whenever a Dynastic non-Groundhog rule becomes repealed due to the effect of the rule “Phil the Groundhog’s dictum”, the title and text of that rule shall be appended to the Parallel Ruleset and becomes a Memento.

To “Flashback X” means to take a Memento with a title of “X” (if it exists) from the Parallel Ruleset and appending it to the Dynastic Ruleset, preserving it’s title and text.