As qlproxy acts as ICAP server for Squid, then Squid passes all *contents* of request/response to qlproxy stripping the IP connection information. So the recommended approach is either to block access to specific IPs on your firewall (not good know) or just prohibit browsing with IP addresses instead of domain names in each policy. Then any GET url/blah/blah will be blocked completely.
BTW shall I add
iheart.com to radio, music category so that you block the whole Radio/Music category? It is much easier that manually adding all radio stations...
Best regards,
Raf