What you described would involve pretty significant changes to the program data structure and UI. It’s better addressed by using an external script. You can write a script in Python or any suitable language that sends HTTP commands to OpenSprinkler to turn on zones in any sequence with any delay time. You can create as many scripts as you need. Please check the API documentation, particularly Section 10. Test Station (previously manual override) command:
https://opensprinkler.freshdesk.com/support/solutions/articles/5000405359-opensprinkler-firmware-2-1-0-api-documentation