Kerbal Space Program

I have at times wanted to activate an action group with a particular stage, but currently this is not possible as far as I can tell.

With the KAL-1000 in Breaking Ground there is an obvious way to make this happen: Add a simple activator part to the base game that is massless (or not), default staged, and appears in the action group list like the KAL-1000 but rather than having a separate editor it just triggers all assigned actions. This could also be useful unstaged to allow the same set of actions to be activated from multiple action groups without needing to copy the full list, to allow subassemblies to come with defined sets of actions but unattached to any particular key, and for robotics when simple activation is all that is required. While ideally this part would be in the base game, if the logic is only in breaking ground then adding it there would be fine too.

Another option would be to allow KAL-1000 to be staged, which would be nice even if a core game alternative is created. KAL-1000 can do things like enable engines, slowly increase thrust, at a certain point release the clamp, and run a small light show while all that is going on so it would be nice to be able to stage the start of that sequence.

Another option would be to have in addition to the general stage action group another action group for each currently existing stage. However, this seems more likely to lead to unintended behavior when stages are moved or changed.