Create VOIP service with messenger / dialler that has unique set up...2

We need to discuss what you are capable of before agreeing bids and prices so please contact me... THE PROJECT BASICS: I would be happy for the developer to combine together already existing open source software to create: A messenger / dialler interface. The messenger will have these key features: 1. Auto-Answer capability. 2. A pre-created HIDDEN contact list with contact details that we have inserted there.. this list is not visible to the customer. No contact list is required for the customer so happy to have the facility or not but the hidden list is essential. 3. An automatic change of status when busy on a call. 4. Software that can identify and call the FIRST available (i.e. not busy on a call) contact. The messenger / dialler will not work in a "normal" fashion - when a customer with an account types a phone number they wish to call the messenger / dialler will appear visibly on the customer screen to be making the call, the dialler / messenger will simply send the desired phone number to our computer AND it will call a contact from the preset contact list. A customer account and billing system will be integrated with the system and other automated initiations will be integral in the system but they can be dealt with as separate projects.