If you go to the Common Ground web site, there are FAQ, including,
What's Common Ground? It's one organization in a national network affiliated with the Industrial Areas Foundation (IAF), the oldest and largest institution for professional organizing in the United States.
IAF was established in 1940 by Saul Alinsky. He discusses this extensively in his book Reveille for Radicals (1946).
"Our" Milwaukee Catholic Herald apparently decided all this wasn't worth mentioning. It does say,
One of the Catholic organizations to invest in Common Ground is the Catholic Campaign for Human Development. Common Ground received local (archdiocesan) grants from CCHD of $5,000 from 2005 through 2007 inclusive. It also received a national CCHD grant of $40,000 in 2007.
It also tells us of a letter from Milwaukee's bishops to Common Ground.
"... The fact that numerous Catholics, 17 parishes, several religious congregations, as well as several Catholic colleges, are members of Common Ground demonstrates the vibrant faith of the Catholic community in southeastern Wisconsin," they wrote.