Multiple shape with different opacities on top of each other

I am trying to create an illustration with multiple gradients, also with less opacity. I am just struggling with how I can make sure the other layers won't be visisble. Just created a quick example to clarify what I want to achieve. The yellow/red layer needs to be on top of the white/blue layer but I don't want the blue layer to be seen through the lower opacity yellow side. Is there a way I can manage that?