The procedure is simple.

The employer shrinks the hospital and doctor network to make the company plan unattractive to those with chronic illness. Or, the employer raises co-payments for drugs needed by the chronically ill, also rendering the plan unattractive and perhaps nudging high-cost workers to examine other options.

At the same time, the employer offers to buy the targeted worker a high-benefit “platinum” plan in the marketplaces. The plan could cost $6,000 or more a year for an individual. But that’s still far less than the $300,000 a year that, say, a hemophilia patient might cost the company.

The employer might also give the worker a raise to buy the policy directly.

The employer saves money. The employee gets better coverage. And the health law’s marketplace plan—required to accept all applicants at a fixed price during open enrollment periods—takes on the cost.