Setting individual alpha values for Model.Meshes

I have a single model composed of several Meshes. I would like to render some of the meshes with partial transparency, and others as fully opaque, so that the opaque mesh may be seen behind the semi-transparent mesh. However, after setting the BlendState to BlendState.AlphaBlend and manually setting the Alpha of each BasicEffect in the desired mesh prior to calling mesh.Draw, the partially transparent mesh fades to the background color, rather than revealing the opaque mesh behind it. If I had to guess I’d say this is most likely a z-culling issue on Monogame’s part. What would be the recommended way to achieve meshes of varying opacity within a single model?