I think you will see what I'm trying to illustrate. An additional flood on the backdrop in a studio setting will result in additional dimension to the image. Generally, you want to use at least three light sources on your subject. If it is to be a group shot, more light sources may be required. A very common oversight is when a group is photographed, they are generally not in a single row or line.
Some members are in front of others.
Lighting becomes extremely important in situations like this as you want to avoid one person casting a shadow on another person. Film will capture every flaw in the composition so attention to detail is a must. Whenever possible use strobe flashes and quartz-halogen lights. Avoid tungsten, incadescent, or flouresent light whenever possible as they have something called a color temperature which will grossly affect the color in color images if they are not properly filtered and handled. It is also important to remember that light intensity drops off rapidly as you get further away from the light source.