Organizing OnGUI into Multiple Functions

"You can only call GUI functions from inside OnGUI"

I would love to put OnGUI into multiple functions, so it's not so messy, for example:

 public class GUIStuff : MonoBehaviour {
     void OnGUI() {
         CrossHair();
         HealthBar();
     }
 
     private void CrossHair() {
         // obviously not a significant amount of code, but just an example!
     }
     
     private void HealthBar() {
         
     }
 }