SQUID to work with an antivirus (clamav, bitdefender or kasperski)
 

I have a router for an internal LAN, i use squid for HTTP and FTP proxy cache and I want to setup an antivirus so when somebody download a file from the internet, the antivirus will scan the file and block it with an error message if the file is infected.

I want to ask which is the best software for this ?

Regards,
Imran