Inserting a Diacritial Mark to Replace It With Another One.

I want to know if this is possible in Font Creator. I’ve seen this done in various scripts in Microsoft Keyboard Layout Creator. It involves combining diacritical marks where I press a key to insert the mark on the character. But, then when I press another key a new diacritical mark replaces it on the same exact spot.

This image should further illustrate what I’m trying to say here:

This might be possible with help of specific OpenType layout features.