As far as I know, it isn't possible.
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I don’t know the answer but here is what I’m thinking based on the fact I also own a Supernote. I think you should be able to export the pages you want from the Supernote as a PDF and then drop those pages into the RM as the PDF. Then move the PDF and when asked where into the PDF File. Once you do that you should be able to hit the four square buttons and rearrange your files if they are individual pages into the order you want within that PDF file. I use non-remarkable templated PDF’s for my journals, project planning, finance, and meetings. You def should be able to create a sub folder if anything to store the PDF. I may not be right here but try it and see.
I don’t think you can move PDF pages outside of a file, only within the file. I would use a PDF editor on my computer to combine them. They generally cost money, but maybe there are free ones? Adobe Acrobat comes with Creative Cloud if you have that. I’ve used https://www.pdf-xchange.com/product/pdf-xchange-editor for years, but it looks more expensive now. There are probably online tools that could do it if you don’t mind copying the files on a website. Or we could ask rmhacks to add this to his RCU utility.
i think you can export the pages from your Supernote as a PDF and then add them to the RM as a PDF. then rearrange the pages if needed. or you can use a PDF editor on your computer to combine them. there might be free options online too.