if the call-back may happen in an different passage, then this could be a step towards solution:
Protagonist makes a phone call and says
"<<link "Hey">><<set $call to "w1">><</link>>" or "<<link "Hi">><<set $call to "w2">><</link>>" or "<<link "Sup">><<set $call to "w3">><</link>>"
... some other text ...
Later that day, a call came in. Protagonist took the phone:
From the other side, Protagonist hears:
"Hello, my friend, you don't know me, but listen carefully ...."
"Darling, you won't forget to buy the meat for this evening, will you?"
"Police departement calling. Inspector Henderson here. Did you receive an unusual phone call this afternoon?"
... How will the story go on ...
This is my first try with sugarcube, so this solution might be the worse, but anyway, it looks like it is working. I would expect that one could <<include>> whole passages instead of writing 'case' the sentences down right there.
If you meant to display the different text variants to display on the same passage - immediately after choosing what to say - then there must be found a binding between "show/display text" and the triggering link.