Best way to unpublish content automatically (rules? scheduler?)

Hi,

I have a Drupal 7.20 site, I have a custom content type for our "employee lists" that is automatically populated nightly using "Feed Import" feature.

This works great, except I would like to be able to also "unpublish/delete" employee list records of users that are gone, so basically users that have not been updated by the "Feed Import" over X amount of days (which translates into the user not existing anymore).

The feed is setup to update existing records, so user accounts that exist will always get an "update" when the feed runs.

Right now, we would have to go in manually and unpublish/remove the content, is there a way to do this via some module such as Rules?

I want to be able to unpublish custom content type that has not been updated, or even better if we can unpublish content based on a value on a field for the content type.