In the new app versions released today, you can assign a Song Auto-Selection trigger to an action as well as Song Selection and Song Second Selection. You can also assign multiple triggers to the same action. So with a setup like Ahiru's, you could assign Send MIDI to Song Selection, and assign Start/Stop Automation Track to Song Second Selection and Song Auto-Selection. Then the MIDI will be sent when selecting a song automatically or manually, and the automation track will be started when selecting a song automatically or selecting it twice manually.
A song auto-selection will trigger Song Selection and Song Auto-Selection actions, but a manual selection will only trigger Song Selection actions.