Can you make a system that manages DeathByExplosionComp & StoresComp ?
When a storing entity is destroyed by explosion, it processes all the stored entities, giving them a chance to be destroyed in the explosion, and a chance to become parentless.
Your undestroyed cargo will then lose its StoredInComp and will manage its own positionning, lost in space. the exlosion blast entity will push it in the correct direction.
Something like that?