What vehicle and engine? Based on the remark of "first 3" and "back 3" I'm going to assume it's a V6. Most Hyundai V6 engines require the removal of the throttle body and upper intake manifold to access the rear plugs.
I don't own a Santa Fe but the 2.7L V6 in the Santa Fe is that same engine as the 2.7L V6 in the 2003-up Tib (with some minor differences to fit the different chassis. Below are 2 links on how to do iton the Tib. It should be the same for the Santa Fe.