Integrated luminosity of SMBH sources ($L_{\mathrm{BH}}^{\mathrm{vir}}$) for each galaxy in the 0.5–2 keV energy band as a function of the accretion rate of the central SMBH (Ṁ_∙). The dashed line indicates the upper limit set by the bolometric luminosity of the central SMBH (see criterion 3). Data points above the dashed curve host more than one X-ray bright SMBH source within R_vir. Each galaxy is color-coded by the ratio ℓ (Eq. (3)) between the integrated luminosity of SMBH sources and the other two components (gas + XRB). Galaxies that have been excluded following our AGN classification scheme are highlighted by thick edges and have been removed for the final sample.