Rejecto doesn’t currently work with grammars, but yes, you would need a license for each bundle ID. Generally in these cases I can give you a discount if it’s very clear that the bundles are for the same shipping app, so email to discuss that.
If your grammar is frequently picking up random utterances that can sometimes indicate that it doesn’t have a lot of complexity – can you tell me a bit about the grammar? How many words/syllables are in a legal utterance in your grammar?