Capital spacing included in stylistic set

I’ve this font in which I’m including all case sensitive forms, lining figures, all caps etc all inside a stylistic set, due to the fact that certain softwares do not recognise ot features but do work with stylistic sets.
So now when I apply ss01 everything works fine (same as if I activate all caps feature in indesign) but I cannot find a way to include extra capital spacing. I know for sure that it is possible because I’ve another font which does it.
Anyone knows how?
Thank you.

From page 94 of the Glyphs handbook:
“Some features and classes can be generated automatically, but need to be inserted manually. To do this, click on the plus button, and choose All, All Letters, or Capital Spacing from the menu that pops up. The class All contains all glyphs, All Letters contains all glyphs categorized as ‘Letter’. Adding the feature Capital Spacing (cpsp) adds extra space between capital letters in all-caps typesetting. It will also trigger the Uppercase class, containing all glyphs of category ‘Letter’ subcategory ‘Uppercase’.”