You basically reinvented families. It's a license-only feature, but it pretty much allows you to do what you seem to be looking for.
It's also possible to make several "families" with a single object type but using several animation frames.
For example if the modification is mostly visual you can go something like this : example capx.
I often say, it's nice to make new behavior and stuff, but C2 is already powerful enough to handle a lot with the common/basic system available, and it's often a mistake to try to expand it when it's "easier" to go with what's already in.
Unless I'm proven wrong and there's something I'm overviewing (which can very well be the case), I'd rather not add this behavior to the list as the basic event/features are already capable of this.