Asterisk Chat room VoIP

1)i would like to have some chat room developed in asterisk software or any other software 2)the chatroom will be "reserved" when an external server to asterisk, sends a request to the asterisk box to have a chat room and password assigned (via XML or some other command you recommend) 3)the chatroom should allow temporary access to users which have the access code after calling some DID number 4)the access code to the chatroom should be generated to the asterisk and will be send to an external server, via XML or using GET command or something like that. 5)the challenge would be to have it hosted in a public hosting service (based on your recommendation)or some other hosting 6)If you could provide a DID number would be great but it is optional. budget is US$250