Migrate Mendeley folders into JabRef subgroups

Hi everybody,
I am moving from Mendeley to JabRef. So far I’ve imported my database through BibTeX database, but I would like to keep the folder structure from Mendeley. Is there any tool that would help me with?

The best way so far would be to export into bibtex files for every folder, but I have close to 100 folders in my hierarchy and I would avoid that if there is any possibility to do it otherwise. I’ve already searched for it, but have not found any solution. To be honest, I’ve found very few instructions how to migrate from Mendeley.