The Disney Channel shows "High School Musical" and "Camp Rock" were both produced by Disney Channel, but Hannah Montana was also a Disney Channel show.
They were all successful shows that launched the careers of many stars, including:
* High School Musical: Zac Efron, Vanessa Hudgens, Ashley Tisdale
* Camp Rock: Demi Lovato, Joe Jonas, the Jonas Brothers
* Hannah Montana: Miley Cyrus
So, while they weren't all made by the same production company, they were all part of the same network!