Hmmm, every task is totally independent. So the answer is probably no.
> Is there any way to do it so that, at some point in the future we may have
> orthogonal classifications, like for example
> {0-3,3-6,6-12}x{educational,game,toy,development,office} ?
While you could for sure create tasks like this
educational-age-0-3
educational-age-3-6
educational-age-6-12
game-age-0-3
game-age-3-6
game-age-6-12
toy-age-0-3
toy-age-3-6
toy-age-6-12
...
and than create metapackages like
age-0-3:
Depends: educational-age-0-3, game-age-0-3, toy-age-0-3, ...
age-3-6:
Depends: educational-age-3-6, game-age-3-6, toy-age-3-6, ...
...
and
educational:
Depends: educational-age-0-3, educational-age-3-6, educational-age-6-12
...
I would consider this pure overkill. We intended to keep things simple
and so this should not be a proposal for a solution. Just to explain
chances and limits of the tasks approach.