Based on the effect of a shot-noise suppression in mesoscopic circuits comprising several single-particle sources we propose and analyze a method to compare states of emitted electrons. We analyze both a regularly emitting source and a stochastic source of electrons and holes. In addition the multi-particle source (a double-cavity quantum capacitor) and the commonly used metallic contact, as an electron source, with either constant, periodic in time, or carefully shaped Lorentzian-pulse voltage, are analyzed as well. We show that collision of wave packets of a close shape at the QPC leads to suppression of a current cross-correlator for all considered types of sources. This suppression effect takes place even if the incoming flows are noisy and/or if the wave-packets carry different number of particles. The noise suppression results from fermionic (due the Pauli principle) positive correlations arising between colliding particles.