Sending content to Transifex using a Transifex Native SDK will append phrases in a single resource. So that resource will keep expanding as more phrases are added to it during development. To categorize phrases of a Native resource you can ask your developers to use tags, or add tags through the Transifex editor.
In order for developers to add tags on a specific phrase, they need to use the specific syntax that Transifex Native offers. Read more about tags here.