You don't need the headphones to pair with the soundbar you need to pair them with the TV.
You can't pair both to the TV at the same time even if the TV has a bluetooth transmitter built in. You could pair one at a time or add a BT transmitter that could pair with both the soundbar and headphones at the same time.
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/www.amazon.com/gp/product/B00QV77YIC/ref=ox_sc_act_title_1?ie=UTF8&psc=1&smid=A3M9LKZ5UKEHJ2&tag=tbpre-20