Bring forward an object by clicking a button in Powerpoint

I have a PPT presentation with some slides. In each slide I have some superposed images and some buttons (see example image). I would like to "bring to front" an image when the corresponding button is clicked. I have been triying with animations, but unfortunately there is no animation to run this action. After some 'investigation' I think that the only way to achieve that is by a macro.

I have absolutely no experience in VBA programming, but after some search I found out the way to 'bring to front' an image of the active slide by doing:

Sub Bring_front()
Dim sld As Slide
Set sld = Application.ActiveWindow.View.Slide
sld.Shapes("NUCLEI").ZOrder msoBringToFront
End Sub`

Then I insert an action (to execute the macro) to the correspoding button and everything works fine!

The problem is that in my real presentation I have many images and buttons (like 10 for slide)... and I would like to create a macro with if/else statements in order to run an statement if a button is clicked. I have also been searching how to do that but I have not been able to get it.

Is it possible to do something like that?:

Sub Bring_front()

Dim sld As Slide
Set sld = Application.ActiveWindow.View.Slide

 if Greenbutton is clicked Then
      sld.Shapes("GREEN_IMAGE").ZOrder msoBringToFront
 elseif Redbutton is clicked Then
      sld.Shapes("RED_IMAGE").ZOrder msoBringToFront
 elseif Bluebutton is clicked Then
      sld.Shapes("BLUE_IMAGE").ZOrder msoBringToFront
 end


End Sub

Can someone help me with this, please?

Thank you in advance!

Maria