Android Application Development

I need an application to connect two phones via Bluetooth such that Phone A acts like a standard wireless Bluetooth headset which is connected to Phone B. Over and above using dialer of Phone A we should be able to make call through Phone B. For incoming and outgoing calls on Phone B we should be able to attend those calls through Phone A. Application should be installed only in Phone A to make this work. Practically we are trying to give additional call dialing feature to standard wireless Bluetooth Headset i.e Phone A.