I've seen a "school" of tangs in various tanks at Absolutely Fish in Clifton NJ . Depends on the individual fish but it didn't seem to me that they were bothering each other. Then again I only observed them for 20-30 min..
Just want to make clear that I'm not contradicting what cali reef suggested. It's good advice not to put two of the same tang species in the same tank unless they have enough room . I was just noting some observations.