How to get supervisor's Person Type through Autocomplete Rule?

Summary:

Need an Autocomplete rule to restrict the Person Type of Line Manager to be Employee only

Content (required):

Need a Autocomplete rule to restrict the Person Type of Line Manager to be Employee only, so that won't select intern or contractor as manager by mistake.

What's the approriate business object to use, as there are multiple transactions can change the manager: Change Manager, Transfer and so on?

Version (include the version you are using, if applicable):

22B

Code Snippet (add any code snippets that support your topic, if applicable):

How could the autocomplete rule to get the person type of the line manager?