There should be several banters between each of your party members. Normally when they turn to each other that is a sign that a banter will begin. If you added the banter accelerator option, be aware that you will run out of banters quickly for some NPCs. A few like Althon/Aesdale have many but some NPCs still only have 3-4. You could run through them in a day of game play and now have nothing left.
No accelerator
Most of the time my party was Dirbert, Rilithar, Vildamyr, Rihn, Alton.
There were dialogs between Vildamyr - Rihn and Rihn - Alton but nothing more.
Sorry for my english :/