Homebrew golem stacking?

[The-0-Endless]

Does anyone have any idea how to, as a DM, play up layered golems?

What I mean by that is, how would you play a colossal iron golem that, when killed, falls apart to reveal two gargantuan flesh golems that when killed fall apart to reveal four meduim bone golems (each).

This is an idea for a city defender golem used by the BBEG in a mid-level campain. Are there any suggestions on how to play it, or ways to balance it correctly? There will be four iron golems to start, and the party consists of 14th level : thief rogue human, bear totem barbarian half orc, GOO pact warlock tiefling, a human evoker, and two twin green dragonborn oath of ancients paladins.

[Hanuman]

Does anyone have any idea how to, as a DM, play up layered golems?

What I mean by that is, how would you play a colossal iron golem that, when killed, falls apart to reveal two gargantuan flesh golems that when killed fall apart to reveal four meduim bone golems (each).

This is an idea for a city defender golem used by the BBEG in a mid-level campain. Are there any suggestions on how to play it, or ways to balance it correctly? There will be four iron golems to start, and the party consists of 14th level : thief rogue human, bear totem barbarian half orc, GOO pact warlock tiefling, a human evoker, and two twin green dragonborn oath of ancients paladins.

Well you should start by posting the monsters you would like to adjust, and in what version.

I mean you could just balance this to CR, but you should ask the main forums for that before moving it for adjustment?

[JNAProductions]

I think this is 5E, by the class references.