Issue application internal candidates for job opened to Agencies

Summary:

We have a lot of requisitions that we don't want to post in the external career site. We want to keep them internal in order to share them to agencies or to add manually candidates to them. For this reason, we open them for sourcing and we specify yes in the following field "Allow Candidates to Apply When Not Posted". We noticed that, in this way, also internal candidate can apply to these jobs. We want to avoid this behavior. How can we do?

Content (required):

Disable apply button for jobs opened to agencies but not posted in external career site