In a Writer document, is it possible to automatically run a macro when the selected value of an Input List (or other types of field) is changed?
The details provided in this question should be of assistance. The example file in both the (linked) related bug and AOO thread contains a macro that will be similar to what you require. You essentially need to create a macro that ‘listens’ to you desired document object and then link that macro to the Open document event. Detail on the UnoListener function is here.