Instantiate scripts with class relationships

I want to create clones of my behaviours (by using GameObject.Instantiate()), but sometimes they have relationship with objects that are not behaviour. In this case, Instantiate would create a game object with null references for these relationships. I can make these classes serializable and use the SerializeField attribute, but they'd show up in the editor, which would be a mess. Is there another way to do this?

Example:

 public class CloningTests : MonoBehaviour
 {    
 [SerializeField]
 private SimpleObject SimpleObject;
 ...
 }
 
 [Serializable()]     
 public class SimpleObject
 {
 public int number = 0;
 ...
 }

That would work but SimpleObject would appear in the editor.