CLion link external source files into workspace

Hello,

I'm trying to port a project from STM32CubeIDE (Eclipse based) to CLion.

I have source/header files that are not in the root project folder. They are on a higher level.

In STM32CubeIDE I was able to link an external folder in the workspace and compile the folder contents.  Can I do the same in CLion?

To rephrase the question, do the source files have to be in the root project directory to be compiled in CLion?

Thank you in advance :)