Simple question, can I do a one-to-many substitution in an AAT font?
I tried doing an insertion followed by a contextual one-to-one substitution, but the insertion didn't work. In fact I couldn't figure out how to make Insertion work at all.

Reason:
I want to split up some Indic compound vowel signs (which have unicode codepoints) into the base parts so that I can insert other glyphs (vattus) in between.

- Nicholas