swarm in object in object: where to put observer

[Ludo Pagie]

Hi all,

raising (slowly) from lurker3 to lurker4 I just wondered (don't  know yet if
this will become a 'real' problem);

Suppose you build a model in which the top-level swarm contains an object,
which contains another object, which contains another object, which contains a
swarm (of objects). Now who should hold the observer for the last swarm.

Obviously not the last object; 'agents' should not contain observer-tools.
But (obviously ?) also not the top-level swarm, that would lead to  problems in
the maintainance, etc.

Does a design principle exist for this sort of construct?

Again; I was just wondering.

Ludo.