google bigquery – Move policy tag to another tier without losing policy tag being removed from columns

We have a defined a taxonomy with every policy tag at the same tier level, like this:

  • Policy_tag 1
  • Policy_tag 2
  • Policy_tag 3

Now, we want to have those policy tags one nested into the other, like this:

However, we’ve already assigned those tags to multiple table columns, and we couldn’t find any way to move the tags besides deleting and recreating them (which would also lose the columns current tags).

Is there a way, from the GUI, CLI or API, to nest the tags while keeping them assigned to the columns?