  Statistical characterization of secondary subsystems in binaries helps to
distinguish between various scenarios of multiple-star formation. The DSSI
speckle instrument was used at the Gemini-N telescope for several hours in 2015
July to probe binarity of 25 secondary components in nearby solar-type
binaries. Six new subsystems were resolved, with meaningful detection limits
for the remaining targets. The large incidence of secondary subsystems agrees
with other similar studies. The newly resolved subsystem HIP 115417 Ba,Bb
causes deviations in the observed motion of the outer binary from which an
astrometric orbit of Ba,Bb with a period of 117 years is deduced.
