If you are planning on using the brakes you need a brake controller. Any other arrangement would be either no brakes or full brakes.
Since you also have another trailer I would assume you already have a brake controller in your tow vehicle.
I am assuming you don't mean a brake resistor which used to be used with older controllers for fine tuning. I haven't seen that done in years although I did put one on a horse trailer with 6 volt brakes .
I am also assuming you do have electric brakes, not some hydraulic system?
Rick Davis 1602 K8DOC
61 tradewind, plus a few others
13 Ram 2500 TD
99 Dodge TD 577K miles