With custom variables, you can create a variable that can be used in any Hierarchy.
To do it:
Open the add-on menu on the Jira Navigation bar
Click on the “Create variable” button in the Variable section
Enter the Name and Default values
Click on the “Create” button
Now when you have Custom Variable you can use it in text fields of Hierarchy Node
You can manage your custom variables on the ‘Manage Variables’ page:
Open add-on menu on Jira Navigation bar
Choose Manage variables