I need help with Xbox 36 online set up?

I have two gamertags needing to be used (brothers and mine) I buy a gold cad today, scratch off get the code and put it in. The problem is it only works for one tag and not the other. Didnt have this problem with the free silver membership that came with the 360. How do i connect them both to the same card.I need help with Xbox 36 online set up?
You need to buy two seperate Xbox Live subscriptions.





Each gamertag needs it's own.

inc.

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