Is it possible to make a script, run it, and a function is called every time an event happens.
In RoboFont it is addCallback.
Example: Every time a hint in placed it triggers the AddHintCallback, and this has a function that will copy the new hint to all masters.
(I know we only have to hint the first master, but that is not good enough for our use, we want to see the thickness of the stems. By hinting them it will become visible and the glyphs are hinted in the same time.)