Blocking services like whatsapp

Yes, I’m also aware that some apps (whatsapp, gmail, megasync, …) use other kind of connections like SOCKS, which bypassed NS7 web proxy. Could you tell me how can control this kind of connections? I already set some rules, but I haven’t find a setup that accommodates my needs.

I would like to deny all traffic except to:
A [host group] (called internet-pc) which would be able to surf the Internet
Any request going over squid

squid is only a http and https proxy. Other services you have to block with firewall or IPS.

For whatsapp you can read here: