This feature (select phone to ring) is great. Just one small suggetion...Instead of displaying the number of the phone to ring could you return the label/name of the phone to ring? For example instead of the pop-up showing:
555.555.5551
555.555.5552
555.555.5553
etc.
Could it just say:
Home
Office
Gizmo
etc.
For me, it would easier/quicker to differentiate the buttons if they were text instead of numbers.