On 15.5 SP4 currently, and I have an interesting situation. We have a site wide ring all setup based on an inbound DID for use when the building alarm is triggered. We have some users that use the call forwarding feature at the handset level on their Yealink T46G desk phones. I've also dug through the call forwarding features built into 3CX itself. Is there any conceivable way to prevent particular call queue's or DID's from being forwarded externally? I haven't been able to find anything yet..