And, fwiw, most authorities strongly advise against having anything to do with the Master document feature.

If your boss has budget to spare and doesn't mind waiting while you get your head round a new approach – yes, I do realise these factors add up to a wildly improbable situation – you can get him to read up on DITA Exchange: SharePoint, a Word-like interface, and the possibility of assembling reports (or other documents) from a selection of separate topics. Regrettably, my boss doesn't have the budget either :-{