Denoiser doesn't denoise partially transparent objects

I want to create an X-ray rendering where the partially transparent objects have an alpha pass. Problem is, that no Denoiser in Blender will denoise anything that isn’t at an aplha value of 1. As you can see in the pictures, the opaque objects have been denoised, but the plane with the alpha <1 is untouched. Is there any solution for that?