How media urls can be kept consistent if media models are newly created with the same images for a product when there is a media update ?

For our application we are sharing media urls of a product with some external partners.Now there is a requirement of making those urls consistent since for a new media update of the product entire media model is removed and new media container and media models are created.Since the media models are removed and newly created the urls for these also changes.How can i keep these urls consistent? We are preetyfying our urls as well.Please adivse.