  Large samples of \Lambda, \Sigma(1385) and \Xi(1321) hyperons produced in
deep-inelastic muon scattering off a ^6LiD target were collected with the
COMPASS experimental setup at CERN. The relative yields of \Sigma(1385)^+,
\Sigma(1385)^-, \bar{\Sigma}(1385)^-, \bar{\Sigma}(1385)^+, \Xi(1321)^-, and
\bar{\Xi}(1321)^+ hyperons decaying into \Lambda(\bar{\Lambda})\pi were
measured. The heavy hyperon to \Lambda and heavy antihyperon to \bar{\Lambda}
yield ratios were found to be in the range 3.8% to 5.6% with a relative
uncertainty of about 10%. They were used to tune the parameters relevant for
strange particle production of the LEPTO Monte Carlo generator.
