Medicare and group health insurance?

When you have other insurance, there are rules that decide whether Medicare or your other insurance pays first. The insurance that pays first is called the "primary payer" and pays up to the limits of its coverage. The one that pays second, called the "secondary payer," only pays if it covers any of the costs left uncovered by the primary coverage.

For more information, see the Medicare and You 2009 book:

http://www.medicare.gov/Publications/Pubs/pdf/10050.pdf (page 74)

that page 74 only discussing if you are working. i am not working.