Visual Studio 2017 - Conditional Build depending on server architecture

Question

Wanted a help on conditional compilation in visual studio, I have an SAP library that I use in my environments I need to reference the correct version of this DLL depending on the architecture of the server, for example:

I have some old web sites that are still hosted on 32-bit machines, in this case I need to compile a library that I developed in 32bits to be able to publish in production.

I already have other newer sites that are hosted on another server that the architecture is 64 bits, but in order to use the same library I have to point to the version of 64 bits Dlls and compile.

Before you say anything, it doesn’t solve I set my project to Anycpu, it doesn’t work.

What I would like to know is if there is any way to automate this and avoid that every time I compile the project reference to the correct architecture, I searched and found the link insert link description here below, but not working it ignores the directives and always compiles with 32-bit Dlls

Example Found