1) The office:text element should appear once in a regular document

2) OpenOffice::OODoc allows the programmer to create complex documents including parts possibly extracted/copied from other documents, but it's not designed to directly merge documents.

3) However the API allows you to easily create a master document and include external subdocuments through sections; see the appendSection() method in the OpenOffice::OODoc::Text manual chapter; the result is not exactly a merged document, i.e. the external documents remain hosted in external files, but the functionality is similar.