VMS Help SORT, Output File Qualifiers, /RELATIVE, Full Description  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    If the organization of the output file is to be different
    from that of the input files, then you must specify the new
    organization. If you do not specify file organization, the
    default for record and tag sorts is the organization of the
    first input file. You must use the /RELATIVE qualifier to specify
    relative output file organization.