IS it possible to load the whole game (and all scenes) at startup to avoid scene change delay?

I have a 3D game based on unity and I have made it in a way that all menu screens are different scenes, But loading takes time, and that makes it look like the game is lagging upon pressing a button. Is there any way to make the whole game and all scenes load at start-up and just show themselves when called? here's the code I tried: if (Application.GetStreamProgressForLevel(1) == 1 && Application.GetStreamProgressForLevel(2) ==1){ Application.LoadLevelAdditive(1); Application.LoadLevelAdditive(2); Application.LoadLevel(1);