Vonage and multi phones?

I am currently using a Linksys PAP router with vonage that allows me to make a single phone call with a single account, I'm wondering if there is a VoIP router that would allow me to have up to 5 lines on a single account? Are there other VoIP providers that do have the hardware and such? Since we typically only use two phone lines at a time in our office it seems a little crazy to pay $70 x 5 (Business unlimited) or $350 a month just to hold five account open. Any suggestions