This may not be worth the work, considering that you are going to be using QB actions, but this may be a time saver in the meantime.
You could create a Formula Rich Text field using the Add Record API. Here is a link to the page.
All you would have to do is specify the Field IDs of App 2 and then set them equal to the Field in App1 that supplies the correct value. This above link has examples for XML and URL API calls.