Your 5er will need a custom fabricated receiver hitch welded on the rear. You'll also need wiring back there for the 2nd trailer brakes and lights.
Usually, the 2in. square tube receivers are rated for a 500 lb trailer tongue weight unequalized, and 1000 lb trailer tongue weight with an equalizing hitch. So the hitch type you'll need would depend on how heavy the trailer tongue weight is.
IMHO I'd get the Reese equalizing hitch WITH the anti-sway bars anyway. Why take a chance with all of your expensive equipment going down the road?