... • Don't touch Package/Project A, Package/Project B has to change package to the path of MyLIbraryII. You can now open one library in two seperate projects. Just keep in mind that it's jury-rigged.

I'm getting this specific variation of this issue and I have found a solution. Just trick xcode into thinking that one local library is two: • Close all projects from menu bar or ctrl-option-cmd-w • Delete contents of ~/Library/Developer/Xcode/DerivedData • Delete any Package.resolved, .swiftpm or .build files in ALL packages that are local. • Create a symbolic link to the local library "ln -s MyLibrary MyLibraryII " ...