You cannot link two scene triggers directly to the same scene, but you can achieve a similar effect by duplicating the scene.
To duplicate a scene, go to the scene list (click 'scenes' in the menu bar) and hover over the scene you want to copy. You will see the copy icon (two documents) appear on the right next to the delete and edit icons. Click copy, and the scene will begin duplicating. This can take a few seconds to complete.
Note that duplicating a scene creates a new generated trigger for the copy. You will need to replace this trigger with your own, and the usual process for a new trigger apply - it will take up to 2 minutes to become active in the app, and the app will need to be restarted if you have it open.