Hi @johnstew
I’m afraid you need to create a custom Javascript code to do it. The problem is that repeater field has a complex layout that makes it hard to modify. For something like that you would need to hire a developer to help you out with it, and I’d recommend looking for one on https://studio.envato.com/ or https://www.upwork.com/. You can also check this page to learn how to add custom Javascript code: https://www.advancedcustomfields.com/resources/adding-custom-javascript-fields/.
I think it will be easier if you don’t need to show the generated items right away. That means that you need to update/save the post, which reloads the editor page, to show the items. To do that, you can use the acf/save_post hook and the update_field() function to update the repeater value.
I hope this makes sense 🙂
