Thanks for that, I have seen a couple similar boxs about as well. I am also thinking, as I can get a call box which basically consists of a microphone, speaker and momentary switch I might just put in another media director and rig the mic and speakerphone to that and send the momentary switch to one of my GC100's. I take it then I can just use the intercom function in telephony with a bit of programing of an event etc.
If anyone can think of a better way though please let me know, and if that dosnt work I will go for an IP box as you have suggested. Thanks.