Are you familiar with the website Muckety? On this you can look up influential people and see how they are connected. For instance, the organization you just referenced is run by Edward C. Johnson and his daughter Abigail also participates. They are both listed on the Forbes billionaire list, along with George Soros. But they did not support Barack Obama’s 2008 campaign. It is a very interesting site!
Here’s the Muckety for Edward C Johnson III
http://www.muckety.com/Edward-C-Johnson-III/97330.muckety
You might be able to identify several non-profit groups using this link.
Non Profits
http://www.muckety.com/listings/nonprofitsA.html