If I'm not mistaken, each of those Verizon cards is set up for its own broadband account. You can't have them set for the same account. It sounds like you're hoping to do what Cellular One allowed back in the early 90s, a carphone and a handheld sharing a common number to be used only when one or the other was off. I don't believe any provider does that anymore.
Does anyone know if two different Verizon wireless broadband cards, each in a different laptop NOT being used at the same time, can be tied to the same mobile number?