How to access UI button transitions events?

Hi, I want to play a sound when the mouse is over a button and a different one when the user actually clicks the button but the sound for "over" keeps playing when I click the button too. I am implementing the interfaces IPointerEnterHandler and IPointerExitHandler trying to filter the behaviour but the "exit" event is triggered when the mouse is up too, so when I try to click the "enter" event trigger the over sound again . What I need is something similar to what standard button class do to manage Highlighted and Press transitions. Is there a way to listen to transitions events?

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.Events;
5. using UnityEngine.EventSystems;
6. using UnityEngine.UI;
7.  
8. public class ButtonSounds : MonoBehaviour, IPointerEnterHandler, IPointerExitHandler
9.  
10. {
11.     public AudioSource audioso;
12.     public AudioClip overAudio;
13.     public AudioClip clickAudio;
14.  
15.     bool playsound = true;
16.  
17.     public void OnSelect(BaseEventData eventData)
18.      {
19.         Debug.Log("select " + this.name);
20.         if (playsound) audioso.PlayOneShot(clickAudio);
21.      
22.  
23.      }
24.  
25.     public void OnPointerEnter(PointerEventData eventData)
26.     {      
27.         Debug.Log("Enter "+this.name);
28.        if(playsound) audioso.PlayOneShot(overAudio);
29.         playsound = false;
30.  
31.     }      
32.  
33.     public void OnPointerExit(PointerEventData eventData)
34.     {
35.         Debug.Log("Exit " + this.name);
36.         playsound = true;
37.     }
38.  
39.  
40. }