There is a way to make branching dialogues using the questions dialog effect. it would require a lot more trigs that normal, but it would add a lot to the scn.

example:
Trigger 1: Question
send dialog (3 seconds): "<Yes/no question>" (0:00)
questions dialog (1-4 options): "<Affirmative>", "<Negative>", "Package?" (0:02)
here each possible choice would activate another trigger

trigger 2: Affirmative Response
send dialog: "<Happy/satisfied response>" (0:00)
<another questions dialog?>

trigger 3: negative response
send dialog: "<angry/annoyed response>" (0:00)
<another questions dialog?>

trigger 4: explanatory
send dialog: "<explanation>" (0:00)
<another questions dialog?>

and so on and so on. interesting idea, no?