You can make the divider you talking about out of wood chip board and brackets. Use a straight design or an offset design. Your local lumber yard should be able to tell you how to do it exactly Before hanging buy wallpaper remenants and let each child decorate his/her side of the room to their taste. You might want to paint part of it with chalk board paint and they can then write their own slogans, or glue cork board to it for a bulletin board or a combo of the three. Take pictures and let us see how it turns out.