So often when we photograph groups for business or family the question is "What should we wear?" Tracey Attlee of Attlee Photography suggests wearing combinations of up to three colors but no more.
Color harmony in group portraits matters! It attracts the viewer's eye and keeping it moving through the image. If one person has stripes and one person has plaid and someone else is covered in polka dots what is created is "visual confusion". The viewer's eye is confused and distracted by too many patterns and colors. In that situation the faces of the people in the composition become secondary and the whole point of the group shot is lost.
For business, the best way to solve this issue is to bring a few wardrobe choices for the photographer to see. Gentlemen, this includes bringing several neckties to select from. Ladies, bring an extra suit and blouse or two.