Bearded dragons (with the exceptions of Rankins (pygmi bearded) dragons) are not social animals and do better if housed by themselves.
That said, I let my beardies roam about with a pal (a similar sized bluetongue skink) and so far good, they even share salad from the same dish on the kitchen floor occasionally.
Would I house a bluetongue and beardie together, probably not UNLESS they were in a huge enclosure (at least 2 - 3x bigger than the ones they are currently in (4'x2') and had their own hides, basking spots and perhaps even their own food dishes. (Or if I had a special outdoor lizard pit - some people have these in their backyards and house a few species of lizard (all similar sized) in them.
I know of people who house combinations of shinglebacks, bluetongues, beardies for example together in pits. Some people include fresh water turtles in their little zoos, but you need to make sure the lizards can easily get out the water is they get into it by accident.