Have a Legend 6.0 at 1 building. Want to add some extensions a few streets away at another building. Can we add another Legend at this building and integrate the 2 so receptionest can answer at one building and transfer to extensions at the other building. Would it be less expensive to change out system w/ some type of Voip system, or keep Legend and add another Legend at other building. Would we need T1 cards, etc...?