In a social gathering, referencing other people is easy amongst peers - you could even say 'that guy' or just call him by name, 'Bala'. With elders, though, it is difficult with the elderly ladies. I've always had a bit of hesitation in naming a person - 'Who prepared this dish?' 'Ms/Mrs XY'.
Depending on their marital status, the answer can vary: the Guardian style guide says use Ms unless they have specified Miss or Mrs; Time magazine in a non-article says anything is fine.
There is one more specific: British speakers tend to pronounce Ms as Mz, indicating their current marital status is 'unknown'. I've heard it a couple of times on TV shows, so at last there seems to be a solution: Mz.