That will work. If that is the easiest way for you then go for it.

If after zipping the three files for the high range, you sent it as an attachment, and then the zipped three files for the low range as an attachment to the same or another email that would also work and be slightly easier.

However, looking at your post again. It seems that the data for both ranges is already combined. This is fine, there is no need to split it. Just zip what you have and send it. I can handle files with data from two or more ranges very easily.

Remember, do what is easiest for you.