Currently, always all slides of a Slide Chooser content file will be inserted into the current presentation. If you wish to be able to select specific slides, you will need to split up your content file into separate files (down to one slide per file if necessary).Inserting all slides of content is unfortunately a technical limitation imposed by PowerPoint. We hope that with upcoming new PowerPoint APIs we can offer users the ability to select what slides should get inserted when choosing a slides content file.