Restrict supplier users in vacation rule delegation

Summary:

Hi All,

When an employee searches for users to do delegation for approvals, in search we noticed that even the supplier users also appear. We would like to restrict that. Ideally only the registered employees of organization should appear in the search results. Is there anyway we can restrict that?

In the below screenshot, when searching for employee Chris, the first record that appears is actually a supplier user, and shouldn't be appearing in the results.

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