Hi, i'm Jesus Ramirez and i'm Software developer.
i can create this software for you, but the way it will work is a little weird. The software cannot check if you request the url that you have specified unless it watch and monitor the http connections, and in order to do so then a local proxy need to be setted so if the software set the local proxy to monitor the http requests you will not be using the proxy on the proxy list, and if the proxy of the proxy list is used the software will not be able to check if you request the specified ip and will not be able to change the proxy to the next one.
i'll suggest to use another way to change the proxy to be used