as far as I can see, defining the animation groups should be your smallest problem.
you simply need to put them each into its own .ldr file.
when doing this, you can freely choose where the origin in that file is.
your whole scene then simply would be a composition of these separate files
(which, of course, can reference each other).
This way you completely get rid of the necessity to invent a new syntax for animation groups.
And you also completely get rid of finding a syntax to name them: their name is simply their filename.
Which leaves open the animation scripting task, to which I cannot write here yet more because I have not thought enough about it yet...
you simply need to put them each into its own .ldr file.
when doing this, you can freely choose where the origin in that file is.
your whole scene then simply would be a composition of these separate files
(which, of course, can reference each other).
This way you completely get rid of the necessity to invent a new syntax for animation groups.
And you also completely get rid of finding a syntax to name them: their name is simply their filename.
Which leaves open the animation scripting task, to which I cannot write here yet more because I have not thought enough about it yet...