Yes! The Zello PC app allows broadcasting of pre-recorded messages to channels where you are an owner, administrator, or a moderator. This is done by running the Zello PC app in a command line passing the parameters described below. You can use Windows Scheduler to run the command line at a given time(s) or you can create an app using any programming language to schedule different recordings to be played at different times and in response to different events.
/contact -- Required. The name of the channel to send audio to
/audio -- Required. The full path to audio file. The file must be in WAV format.
/report -- Optional. The path to the file where the operation result (success or fail) will be written. If a file already exists, it will be appended. You can use this file to audit which messages were sent, when they were sent, and to use for troubleshooting.
/timeout -- Optional. Operation timeout in seconds. Defaults to 30 seconds.
Find more info and additional options at Github