Within the web module there are Web Triggers which can be used to limit the visibility of a page.

For example, a ‘Date’ trigger can be set up where the action of ‘Hide Page’ is activated on a specified date and time.

You could create a Job Page within your alumni site, then set a Vuture Web Trigger to hide that page on a set date and time. Hiding the page will remove it from the Job board in the site.