how to deal with missing posts

Running a Job Board I decided to hook into the delete function for posts, that are missing in the file and set the custom post status to “expired”. This seems to have a side effect. The next imports still check for the missing posts and try to delete them. Its hundreds of posts by now and growing.

Is the only way to get them out of the import by permanently deleting them by the import?

I could also set a custom field like _expiration-date to have my jobs expire. But would the import drop those posts for the future then?

Thanks! Gabriel