Default Business Phone System via 1 Android Phone?

Any ROM out there tailored to this sort of thing, or anyone know of a good way to do this? I'd like to have someone else answering my business phone and then if the call needs to be passed to me it can be flashed over. At one point AT&T had a home dealio were you could slap your SIM into it and it had functionality for businesses where you could have voice mails for employees and extensions with some forwarding and call flashing abilities. Seems like that isn't offered anymore, can't imagine this ability doesn't exist with some custom apps or OS. Any info would be appreciated. Thanks in advance.