Chemical abundance relations for members of NGC 5272 (colour) and ω Cen (grey). The filled symbols show the reference sample of ω Cen (grey) and the stars of NGC 5272 (magenta) chemically compatible with it according to the GMM (see Sect. 4), while the empty ones (grey and orange colours) correspond to their outliers. The number of stars in each category is reported in parentheses. NGC 5272 is an example of a GC in the metallicity interval of ω Cen, which has a very low chemical compatibility with it (see also Appendix B, available on Zenodo).