You will need to follow these steps:
1. Create the physical location for library B.
2. Register the metadata for library B, pretty much like library A but with a different physical path.
3. You will have to create two dataset views either using SQL or DATASTEP code. Depending on what tool you use, SAS DM, SAS DI or SAS EG, there will be a slightly different approach but the code should be relatively the same.
4. Register metadata of the dataset views.