Yes, users from multiple devices and accounts can edit a story at the same time. First open your story and click on 'Share' located below the banner to the right.

On the 'Invite' tab, you can then add the names or emails of students. You can also invite a tag, a group of students or class, you may have set up on your students page.

Only the creator of the story can add editors.

You can add as many contributors as you like to a story.

You can set the viewing, editing or commenting rights and share it out.