Unfortunately I have not been able to get the Sling Resource Merger to work. I applied sling:hideResource to the field, but that just hides the one I want to keep. Using slide:hideChildren didn't work either - perhaps I was putting it on the wrong node.
In the core List component, we want to group the existing fields of orderBy and sortOrder, with the custom field we are adding (feature), so they are in that shaded gray area. How can we add this formatting to the dialog while suppressing the dialog from the extended component? Our CRX fields are the ones that are in the gray area. How can I remove the fields in the white area without losing the ones in the gray?