This is what I'm looking for as well.
What you are describing is a 'call queue' - you can set it up so that a call coming to it goes to various extensions at the same time, and the first one to pick up gets the call. The call handling in the call queue does allow for it to be sent to another extension (call queue, ivr, etc)
We have ours set to an IVR first with all the calling details, a department choice, etc. - along with the choice to press '0' for an operator call queue. if no one answers the operator queue, it goes to another department so that a real person does answer.
we have about 30 phone numbers total - 800 and local - and yes, you can point them to where you want. Our Burbank numbers go to that office, the direct numbers for certain staff go to their extension, etc.