In order to obtain information on the time sequence and time scale of the production of intermediate mass fragments (IMF) in nucleus-nucleus collisions at intermediate energies it is proposed to analyze correlations between relative velocities of IMF's with respect to projectile-like fragments (PLF) and target-like fragments (TLF). Experimental data on the production of IMF's in the ¹²⁴ Sn +⁶⁴ Ni reaction, taken with the CHIMERA multidetector array at 35 MeV/nucleon, have been analyzed with the proposed method.