Here's the recipe:
* In the Environment, go to instrument 1 that is playing back the chord.
* Create an arpeggiator object.
* Cable the output at the top left of instrument one into the arpeggiator.
* Option click on the cable outlet of your arpeggiator, and cable it into the "Input Notes" object in the Clicks and Ports layer.
* Select track two in the Arrange Window and hit record. It will capture the arpeggiated notes from the chord.
* You need to turn this routing off before playing back the recorded file, or there will be a feedback loop.
* You might want to make a cable switcher button to easily turn this process on/off.
Here's a simple version of it: