The nuclear three-body system, with two halo neutrons very weakly coupled to a heavy core, is studied to investigate necessary conditions for the occurrence of Efimov states. Extending the analysis to the scattering sector, we find that these states evolve into Feshbach type resonances. This behaviour is very similar to the 20 C nucleus in which the occurrence of Efimov states evolving into resonances in the elastic scattering of n– 19 C system has been investigated in recent publications. This work, thereby, extends the study of the Efimov effect beyond 20 C, showing that 32 Ne and 38 Mg exhibit a very similar dynamical structure. These nuclei are, therefore, also candidates for probing experimentally the Efimov effect.