I’m currently under the impression that every single master within a single .glyphs file must share identical kerning grouping. Meaning that it is not possible to have two ‘a’ glyphs in separate masters, with different left and right kerning groups. In other words – the left and right groups for a single glyph are really stored at the font level, more than the master level.
Is this a correct assumption?
Or is it technically possible to have, say, 3 interpolating masters share one set of grouping, and 3 other interpolating masters share a different set of grouping?