Yes, 6 is too many - you put the 6 in and, once you have a pair or two, remove the rest and give them back to your LFS. That's the only way of getting a pair with angels short of buying an established couple or watching adult fish at your LFS for a while and buying those that are obviously paired (which isn't always reliable as, if there is no fish of the opposite sex present, angelfish will 'pair' with an individual of the same sex).