DND status on other phones

I have installed AAstra 6731i phones on a Freepbx system. We Have setup a BLF key on everyone’s phone for the president of the company. When he is on his phone his light is lit and all is good. The problem is that he used his old system to show everyone he was unavailable by putting his phone in DND the old Inter-Tel system blinked his light so they all left hm alone. Can this be done?? I haven’t found a way to do this.