1) To not re-render all fields (I have many forms where I have many lists that are queried from a DB) for every single field modification.

Yes, that should not be the problem. That was what the rendering in groups was for. The method that creates the script does it on a single id, and creates and updater for this part of the page only.

2) I don't want to have to display some fields together in order to have them been re-rendered when one of them has been modified.

That implies adding multiple updates, so multiple scripts to the same input. So instead of adding a "script: aScript" parameter, we probably should have a variant that adds a "scripts: aCollection" parameter. I am not sure how the implementation should look like exactly. You can try simply adding all scripts. Of course: beware of loops, because otherwise the loading will never stop.

3) I am not obligued to use #group: I can use something different, like #dependentsGroups or something like that

Point taken. I misused group here. I probably should have introduced another term. Do you have a good suggestion? I do not think we should couple this to group.

Diego

P.S. If added you as contributor to QCMagritte