The basic situation is this:
I have a Composite View and an Item View. I construct the Composite view passing it a model and a collection. The model data is used to popu
I didn't answer the question. But changing the approach works. Instead of trying to access the 'parent' Composite View from the Item View I access the Item View from the Composite View:
https://github.com/marionettejs/backbone.marionette/blob/master/docs/marionette.collectionview.md#onbeforeitemadded-callback
I can modify the model of the current item view (based on a value in the model of the Composite View).