I think the problem your going to have is if you intend to have six laptops sharing a theoretical maximum connection speed of 384kbps, that gives each laptop 64kbps to use. Dial-up almost.
If your network is work related, you'll be sadly disappointed with it's performance. You'll be very lucky to achieve the maximum speed and worst case you may be automatically dropped to the standby GPRS when 3G isn't available to use for what ever reason.
I've had various data cards for a few years now, and it can be so frustrating using the available 3G or GPRS and the inevitable slow download speeds for one laptop never mind 6!