Action maps for the six groups retrieved from the HC, ordered by descending median metallicity 〈[Fe/H]〉. Stars identified as belonging to the disc using the Toomre Diagram cluster around the right corner [(J_z − J_r)/J_tot = 0 and J_ϕ/J_tot = 1]. In contrast, stars classified as outliers sometimes appear to be from the disc but increasingly occupy other regions of the action maps as the group metallicity decreases, even reaching retrograde orbits. The colour scheme for all groups remains consistent throughout this paper, with outliers always shown in magenta.