Drupal Lightbox to link an imagefield to another

Hello, I am looking for someone to help me with a tiny issue. I have a Drupal 6 website, with a Press content type. In this content type there are 2 imagefields: Cover and Publication. To display Press nodes, I created a view which displays only the Cover image with lightbox. All this is ok. The issue is: I need to use Cover image only as a thumbnail to display Publication image. So when an user clicks on Cover imagefield, lightbox displays only Publication image. Cover image must to be a kind of preview/thumbnail to display Publication image into lightbox. I use Views, Imagecache, Imagefield and lightbox 2. Thank you.