An all female barbershop quartet? That sounds interesting! As to miking----PERSONALLY SPEAKING with that kind of group, I find it best to let them do what they do---and that is blend themselves. If you record each person individually, it's just not the same. Of course you can do it if you wish, doesn't mean you have to keep those tracks later----but this is where I prefer a Figure 8 microphone (or Omni), have them stand in their normal place, and just sing----let them interact with each other, play off each other, make their own level changes, etc. Capture the essence directly this way.