I have a VoIP box setup with Asterisk and using chan\_dongle to provide me with an inbound GSM trunk as well as a couple of DID SIP trunks with local numbers. I would like to be able to have the following call-flow:

* Person ring the GSM mobile number, get's a voice prompt to state they should wait.
* I call one of the SIP trunk numbers registered on the PBX as an inbound route.
* The PBX joins the waiting call to the newly established call, so I can now speak to the person who called me.

At some point I would like to add SMS to the mix to send me a message when someone is waiting, but this is phase 2. Can this be done?

Many thanks.