I don't think there's an easy automatic way. In theory, you should be able to load all the translation into the stage, and unstage all strings one-by-one but those 30. At which state, you would submit them to the maintainers.
However, I don't think it is necessary. How many translated strings are there? If I was that maintainer, I would personally prefer if all H5P module strings were submitted at once. So that I can see and check things in terms of consistency etc. Definitely would work better for me than multiple smaller chunks.