Blizzard are the developer and publisher, so they run one clientID as they have on central source of truth, a users blizzard ID. So a unfair comparsion unless you are running a central user account system for all games, (Blizzard, paradox and others do this, central launcher, cental user accounts)
Yes I assume that we are the owners of all our companies and we have a common website.
It’s not currently supported, unless your organistation owns all the games rather than the developers under you the publisher/top level developer.
Is it possible in some way if we are?