Shea Group and Faction are different things. Shea Group was created by Julian and this is his official place of work for innovation.
But we don't know who started the Faction and when. All we know is that at some point Viv led this secret organization and that Julian is part of it. In addition, it is highly doubtful that all employees of Shea Group could be members of the Faction.
A faction is a small organized dissenting group within a larger one. Shea Group and their collaborators are the larger group. I'm not saying that all employees of Shea Group are members of the Faction. However, it has already been stated that anyone of them could be.