While our headphone splitter works well to share one iPod between 5 students when they are listening to stories, podcast or videos, activities that involve apps are better in a 1:1 or 1:2 situation. We have found one way to get around this.
If a group of students were playing an app, they might take it in turns to have a go with the app while also engaged in another related activity. For example, students could be taking it in turns to play the app Wurdle, while other students play the Boggle board game.