Are you using an app to combine the relays and sensors into a virtual garage door? Or what do you have setup currently? The Zooz garage door app has a feature to add a delay from when you hit open to when it actually opens. You could use this combined with a rule that triggers the siren only when you activate it from Hubitat.
EDIT: So I am looking at my setup and thinking how this would work. This may depend on how you have the external buttons wired to the door/zen17. On mine the wall button is connected in parallel with a ZEN16. So to trigger a siren I think if I looked for door: opening AND contact: closed, or door: closing and contact: open, that should be to two cases where the door was triggered from the hub. If the door was triggered directly, the hub would not know it is moving until the contact sensor has already changed, so it would not be possible for it to be in those states I listed above.
