How would I make these NPCs have a correct hitbox

So I am making some NPC creatures for my game and I just used a normal R6 body and welded the creatures model to them and made the body invisible. So the hitboxes are all wrong, is there anyway I could make these NPCs have hitboxes inside of the worm model that uses ropes for each segment?

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I’m no pro at this, but maybe weld each individual peice to each worm segment?

Thats not what im asking, it needs a actual body instead of the R6 character having it welded to it