You can use a VMware Workstation with a Firewall such as
Sophos UTM Home Edition (info..) -
(Download-Page for software appliance) or another firewall like ipcop, securepoint, pfsense etc.
There you can block the network traffic and use the webproxy, spoofing IPs and DNS. The downside is you have to be firm with these things - i think you aren't because you're asking.
It should also be possible to install your own DNS-Server for your WiiU, block the specific sites and redirect the remaining querys to the original college-dns.