Here's the first part, the rest are in the related section. Go check it out. They say Shalamar was at - one point - bigger than Rolling Stones. Don't know if it's a bit exaggerated, but it's nevertheless quite interesting to see how calculated and business driven they were.
Still, definately excellent music no matter how unoriginal and unauthentic your rock friend thinks them to be.
The same guy/channel has at least same kinds of tv-docus about Minnie Riperton and Melba Moore. Go check them out, too.