Is it possible to skip Position Change Approval only for empty positions?

Hello Experts,

I have the following requirement for Position Management:

• Changes to Job or Grade on an empty position (no incumbent) should not trigger the Request a Position Change approval workflow.
• The same changes on a position with an incumbent should continue to trigger the workflow.

I tried using the available attributes in the approval rule, but I couldn't find any attribute that identifies whether the current position has an incumbent. I also tested attributes such as All Parent Position Incumbents, but they don't return the incumbent of the current position.

Is there any supported way to identify if the current position has an incumbent within the approval rule?