WCG, the San Francisco-based marketing and communications network that’s a big player in healthcare PR, established a new holding company, dubbed W20, encompassing WCG and two sibling firms, Twist Marketing and W20 Ventures.

Chairman and CEO Jim Weiss said the restructuring was necessary to manage rapid growth.

“What we’ve done is over the last ten years to build this firm from the basement of my loft into a 300-person business across seven offices,” he says. “So we’ve basically created a parent company that is on top of this network of diverse marketing and communications companies. The concept has been to create this organically versus through acquisitions, which is generally more painful and contributes toward a siloed environment.”

WCG remains the firm’s flagship, with two-thirds of its employees and offices in San Francisco, New York, LA, Chicago, Washington, Austin and London. The company formed from the 2009 merger of WeissComm Partners and its two acquisitions, ODA and CommonSense Media Group. Twist Mktg, a spin-off based in New York, boasts a staff of about 50. W20 Ventures, with a handful of staff, will serve as an “incubator,” Weiss said, working on “transformational” uses of new technologies.

Bob Pearson will be president of W20 Group. Pearson, a former Dell marketing chief who came on board when the company opened its Austin office, was previously chief media and technology officer for WCG.

The group has its origins in healthcare PR, which was the bread and butter of WeissComm. Communications are still about 80% of WCG’s business, said Weiss, but the company is diversifying into consumer goods, technology and other sectors, while working on more social and digital media and branding tasks for clients. Group revenues for 2011 came to around $48 million.