[ars]

Then you get grounding loops - not a good idea.

Connect all the drawers to a single ground, using only one direction (star, not ring).

[oiuytgfrgh]

Ground loops probably aren't a big problem for a SMPSU - if you are putting power into a metal box you need to have a ground to the metal box.

[ars]

You do need ground, but do it without loops. Grounding loops are a violation of the electrical code (and can be dangerous in certain fault conditions).