Option 3: use child routes. This avoids duplicating the match conditions.
- match:
type: alert_alert
routes: [ {receiver: receiverOne, continue: true}, {receiver: receiverTwo} ]
The 'routes' branch is a separate subtree. Since each of the routes within it has no 'match' conditions, it implicitly matches everything, delivering to each of the receivers listed. You need continue: true on each of them, except for the last.