Ist there a way to keep the nodereference drop down widget (which is also used as fallback) but preselect the given value with nodereference url widget?

Background: I'm using Conditional fields which is a great way to control fields by other field selections. Since a field set by nodereference url widget is a readonly field and no longer a dropdown the magic doesn't work anymore.
You *can* achieve the same thing with prepopulate module but i don't want to make it possible to prefill all fields in all forms.