VMS Help SCA, SET, LIBRARY, Qualifiers, /BEFORE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /BEFORE[=library-spec]

    Instructs SCA to insert the new library or libraries into the
    list of active SCA libraries before the library you specify as
    the qualifier value. If you do not specify a value, SCA adds the
    library or libraries to the beginning of the list.