Using Storage interface outside project directory

Our project currently uses direct php disk read-write calls to store and access certain files. The project structure is something like ~/Code/my-project for the main project and the storage path I'd like to access is ~/Code/parallel-folder. The storage interface by default only works with the ~/Code/my-project/storage folder and any subfolders. Is there a way to modify this behavior in certain instances without overwriting the behavior of the storage interface generally? I.e. I'd like to be able to use the storage function to access the internal project storage folder as normal and ALSO the folder in the parent directory to the project.

edit: I solved this by just changing the local disk's root directory to point to the parallel folder.