Open and hidden strangeness in hadronic systems

We investigate production of \phi mesons and \Xi baryons in nucleus-nucleus collisions. Reactions on strange particles acting as a catalyser are proposed to interpret the high observed \phi yields in HADES experiments as well as the energy dependence of the widths of \phi rapidity spectra in collisions at the SPS energies. It is argued that the enhancement of \Xi- yield observed by HADES is even higher than originally reported if effects of the experimental centrality trigger are taken into account. Cross sections for new hadronic processes that could produce \Xi- are reviewed.