[Freeswitch-users] Delay Bye Message

Hi. I have what appears to be an unusual request. One of my clients has a clause in his contract with the local telco/sip provider that requires the majority of calls to be at or greater than 12 seconds. On a former platform, he has an option called 'Delayed Bye Message.' This option, if checked, allows him to specify how many seconds to delay hanging up the call once leg B initiates the request. So, all calls will last at least 12 seconds. Does anyone know how to do that with Freeswitch? Any help is greatly appreciated. Thank you, Alex Perkins