EVDO Broadband Card

We have issued some EVDO Wireless Cellular network cards. We are concerned
that our users will insert their Broadband Wireless cards when attached to
our LAN creating an internet connection.

The EVDO card creates a DUN. (Dial up Networking) to access the internet.

We are concerned about the security risks of having this become an entrance
in to our network.

Is there a way to set the computers so that when attached to the LAN the
EVDO Wireless card does not work and visa versa ?

Thank you for the help !!!!