If BCBS insures 5 different companies (5 groups), each is not priced to be profitable by itself, but such that the overall BCBS profit level is achieved. Groups that cost BCBS more are subsidized by groups that cost them less. This is also true if BCBS has one company in a group and that company has locations in 5 different states. Most insurance companies already have networks of providers in multiple states/locales.
"The trophy problem has become extreme."