Maybe making it more complex that it needs to be? ;-)
Just designate a number of adjacent preset slots as the source presets, and put all source blocks in there. These are the "master" presets, as in Johan's post. Think of them as a block library. Use their scene fields to describe the blocks. Now link to them in other presets. Done. Execute the Update command when needed.
No need for a complex checking system. If a link is broken, for example because the source preset doesn't exist anymore, the target block simply doesn't get updated, and the link stays in place. It's up to the user to make it work and keep it that way.