I think I recall Khalid & Jaheira occasionally commenting upon one another's interactions with other NPCs, but I don't think I can remember them saying anything to one another except when they were also talking to someone else. So I'm not sure about this, but it might be a matter of who else is also in the party.
You likely already know this, but just in case: unlike in BG2, most of the party interjections/interaction lines do not appear in a dialog box. They'll simply say them as you walk around. I don't actually remember any of them from my old playthroughs, likely because I usually had the volume low and just missed them.
Also, I remember someone on these forums saying that these lines have proximity checks associated with them, meaning that they only occur if the 2 characters are close together. So unless you spend most of the time in tight formation, they may not occur (no idea if this is actually true or not).
Edit: To clarify, when I say they don't appear in the dialog box, I mean that the dialog window doesn't pop up and pause the game like it does if you, for example, initiate conversation with someone. The interjections will still appear in the dialog box during gameplay if you have subtitles turned on.
Comments
J: "It would take a sailor to untie that tongue!"
K: "Jaheira, y-you are s-s-so--"
J: "Beautiful?"
K: "No. I mean yes! That too!"
Also, I remember someone on these forums saying that these lines have proximity checks associated with them, meaning that they only occur if the 2 characters are close together. So unless you spend most of the time in tight formation, they may not occur (no idea if this is actually true or not).
Edit: To clarify, when I say they don't appear in the dialog box, I mean that the dialog window doesn't pop up and pause the game like it does if you, for example, initiate conversation with someone. The interjections will still appear in the dialog box during gameplay if you have subtitles turned on.