Well it certainly isn’t impossible to do. When I built my PC based controller software in Java and then the UI in HTML 5 and Javascript (with Jquery and JqueryUI), it was pretty straightforward to allow any station to go in any order, and even repeat stations within the same program. I just have an Add button that selects the controller and station to add to the program list. On a PC I also allow you to drag and drop program entries so that you can reorder stations that you’ve added.
The thing that isn’t easy to do on a Smartphone or any touchscreen device is dragging and dropping. But you can get around that by having move up and move down buttons at the side of the station name. Click the station up or down button and it moves up or down in the order.