Although I am not experienced KMM dev, but I would like to put my two cents here. My understanding is that shared module is compiled into a framework that is accessible by iOS platform. Now if you want to create another KMM module, and want it accessible, I think you would need to somehow include it's source code in original shared framework (I don't know how), OR compile code of that module into another framework and link it in Xcode. You can check
this article for some direction.