Scheduling can be done with external software: Stereo Tool can be set to poll configuration files continuously. Then all you have to do is to make sure you modify, maybe with automated scripts, the configuration file according to your needs at the time you need the changes to rollout. They will be committed immediately (or with a very little delay). You can test this functionality manually, just put the polling mode on and point it to a file and make changes with Notepad (or similar), save the file and see (or hear!) them happening
Then all you have to do is to automate this file write/replace process.