You can have multiple of them in separate enclosures, but it is NOT advised that you keep them together. Especially if they are both males. Bearded dragons are not social animals, and they are very territorial. If you keep them in the same enclosure, one or the other will almost definitely bully the other, stressing it out, stealing basking spots, stealing food, and many other things. Its even highly likely that they will fight. Many beardies have lost limbs and life due to being housed with another beardie.
The only bearded dragons that can be housed together are two females, about the same size, and with really good temperament. This should ONLY be done by professional Beardie owners and constant supervision IMO, though.