I’ve created kerning groups. And once created the first kerning between two groups and export for testing, Export failed and I had this message: “syntax error at “}” missing No File was created”
You can import the classes in the font view with Font > Import > Metrics and select another .glyphs file.
The kerning is copied from the kerning panel. Select all and copy, switch to the other font, click in the kerning panel again and paste.