Can you post a little more info on the system setup, and versions of all locations, and why you are trying to accomplish this?
There are several ways around this, some more elegant than others, depending on what options you purchased.
Do you have add-on systems like CMS etc etc.
In general, you can forward calls per agent, by vectoring, or even better solutions,depending on your case.
Do you want this as an overflow feature, or as a disaster recovery option?