With Application edition of Solid File System (SolFS), the same storage can be opened by more than one application at the same time only when all applications access the storage in read-only mode. The application can't open the storage in read-write mode, if other application has opened the storage in read-write or read-only mode. The application can't open the storage in read-only mode if other application has opened the storage in read-write mode.
This behavior is implemented by design and there are no plans to change it.
To get around of the above mentioned behavior, you can use OS edition of Solid File System. The storage is actually opened by the driver and many applications can access it at the same time for both reading and writing.
Another option is to create a server process, which will open the storage and handle read/write request from the user applications.