There's a running dialogue between two of my characters. However, I am not using INTERCUT and only one of the two characters will be in frame. The other will be heard through V.O..
Now, here's my question. At the end of the phone call, just as the person on the opposite end (the one off screen) is about to cut the call, another person beside him says something, which can be heard by the person in frame.
How do I go about writing this particular piece of dialogue? Would I need to use b.g? Can any of you cite good examples of how a screenwriter tackled this rather daunting problem?
Note that the person in frame clearly hears what was said; so I reckon it has to be put as a separate DIALOGUE at the end.