I have added a new feature to ModelConverterX. Reading and writing of MSFS model attachments is now also supported. This way you can attach one model XML into another model. ModelConverterX reads the model attachment as a new type of AttachedOobject, an AttachedModel. They can be rendered in the preview like other attach points, but there also is an option (below the show particle effects button) that will render the complete attached model in the preview.