Sharing data between subforms

I've tried serching for this unsuccessfully but perhaps I'm using the wrong serch terms.

Using LiveCycle 8.2, I have 2 subforms: subformA (which is visible, print only) and subformB (which is visible, screen only).

When the user completes fields on subformB, I need the entered data in each field to remain displayed in subformB fields, but also to be "copied" (correct terminology?) to a pre-determined area on subformA.

For example:
1. User enters name and address into fields with corresponding text captions on subformB in the usual way. We'll say the fields are positioned in the top right corner.
2. The user's data entered into those fields, is copied to subformA, to a different area of that subform, we'll say the top left corner, and *without* the text captions

I'm guessing some kind of binding between the subforms may work? But I can't see how to set it up with the standard options available under the object properties binding tab. Perhaps some kind of ... event scripting? (nervous shudder)