For now, the best thing to do is to include information in the Vols Needed and/or Borrower's note field. You can specify that the patron only needs the Blu-Ray copy. Ideally, library staff will notice this information and retrieve their Blu-Ray copy, or set to Will Not Supply if they don't own a Blu-Ray.
It is easy to miss the tiny text of those note fields. If you want to be very sure to get a Blu-Ray copy, you can look at the request when it is in Pending status. The request record contains contact information for the Lending library. You can send the library an email or give them a call to specifically bring it to the staff's attention that a Blu-Ray copy is needed.