Thanks @ben.boeckel. I found the entries doing a google search
"compile_only" inurl:discourse.cmake.org
The discussion for Add only library headers during target_link_libraries() from 3/2021 is pretty much exactly what I’m wanting.
I also see a workaround in Idiomatic way to deal with huge number of include directories, although it means creating two libraries for this, still it’s a step forwards.
Thank you!