I can't help you do this within Hubitat, but it would be very simple to implement using Maker API and Node Red. I am doing essentially the same thing with virtual switches sending HTTP: 'PUT's to Opensprinkler.
I went into Rule Machine and created a schedule. Selected everyday, then selected Sunrise, then pasted in my 7 HTTP GET urls to control the cameras and saved the rule.
It even allowed me to 'test' it. Wow Hubitat is amazing!
Funny, my answer to your question made me look deeper and I found the same thing. Now I am triggering my sprinklers directly from Hubitat instead of my "man in the middle" Node-red. Thank you for asking and making me look!