Add Video Link In Product Listings Oscommerce

We currently have videos that are added through the admin area. This link shows up when you click on a specific product in admin and the buttons on the right hand colum show up with edit, delete, move..... The video button is in there. When I add a video for the product it shows up in the main product listing. We want to make it replace the details button on the product listings page when a video is added for that product. So if a product does not have a video it show the current details button but when a video is added it will replace that button with a Watch button (We will provide) The watch button will be linked to the video. The pop up window for the video and all the other info is already there. One problem I can see is when adding a video to a product the video add feature allows us to add multiple videos. If there is a way to make the video button in the product listings you are going to add use the first video added that would be great. We do have a test site and we will give access to it. Thanks, Jamie