Talked to the creator about it, and sadly it is not possible because the separate files are over 1GB. It is either all in one file, or nothing at all, sorry.
Viewing post in From where you live v0.12 (vore game) comments
They're already using 4.5GB... You can upload multiple files over 1GB each. "Go!Go!PizzaBoy!" is, for example, almost same file sizes and structure. If the dev is using butler to bypass the default 1GB limit already, they should be able to use it to upload the files separately by using channels. https://itch.io/t/1916522/how-to-upload-for-multiple-platforms