You can set up Loaction Awareness, or set up a firewall rule to block wireless access.
How to block all Wireless traffic when an Ethernet interface is active using Symantec Endpoint Protection 11.x
http://www.symantec.com/business/support/index?page=content&id=TECH104970&actp=search&viewlocale=en_US&searchid=1299788551165
Best Practices for Symantec Endpoint Protection Location Awareness
http://www.symantec.com/business/support/index?page=content&id=TECH98211&locale=en_US
Cheers,
Thoams