I tried this from the visible condition of my repeater on my custom document type which inherits from the product document type. I'm not real sure I'm using it correctly, but i can't get it to work, it just disables the repeater on all documents with or without bundles. Below is what I tried.
{% OrderItemBundleGUID != null %}
and
{% CurrentDocument.GetValue.OrderItemBundleGUID != null %}
Thanks for your help.