On Export: Decompose 1 glyph, apply filter, decompose the rest

I want to, in order, on export through custom parameters:

  1. Decompose a specific glyph
  2. Apply a filter (PreFilter)
  3. Decompose remaining glyphs and export

The reason is that I have a glyph ‘x’ that is created from components, that I want to apply a filter to, but I want the glyphs that contains glyph ‘x’ to be updated.

Doing this manually is not an option.