Reply To: Adding some but not all discretionary ligatures

Hi there.
Since nobody replied, I’ll bring up your question.

If I understand correctly, you can achieve what you want by creating a character style with discretionary ligatures ON (Opentype features).
Then, in your paragraph style options, use a GREP style in order to apply the previously created character style to some letters.
Grep query sp|ct will add ligatures to “sp” and “ct” (but not st or any other existing ligature).

Of course, the chosen font must have these disc. ligatures.
You can check if they exist through the glyph panel and choosing display > discretionary ligatures.

See example below (ligatures in magenta for better viewing):

View post on imgur.com

Hope I understood correctly your question…