Change child ranking when Epic is ranked higher

[padraik]

My organization wants the following functionality and I'm struggling to find a solution.

• When
  • An epic has its rank changed
• Then
  • All children of the epic should have their rank adjusted to be higher than children of all epics lower in rank than their parent.

Does anyone have a suggestion as to how I might accomplish this?

We're currently using Jira Server.  I have Scriptrunner and a decent and growing level of proficiency.