Anyways you can not just do this when you plug in the notes. The program will only allow a certain number for each bar. But I read that buy using different "Layers" you can! You have to hold down "SHIFT" and the "AAROW" key "DOWN" to get to four different layers. The other layers will be "dimmed".
The last thing I have to warn when doing this is, plug in the "Main Melody in first", then let the "accompany parts" on other layers in order of Hierarchy.
"Hierarchy": Any system of persons or things ranked one above another.