Left panel: radial velocity histogram (corrected to heliocentric velocity) of spectroscopic targets in HCG 22 (red) and HCG 90 (black). The group members at around 2700   km   s^-1 are well separated from foreground stars and background galaxies with extreme velocities (not shown for clarity). Right panel: cumulative radial distance distribution of the HCG compact members relative to the central galaxies (NGC 1199 and NGC 7173 for HCG 22 and 90, respectively). The samples in this panel are restricted to the UCD mass range. The KS-test probability of both distributions having the same parent distribution is 0.9%.