And, no, they’re not related, and they’re not named Lata or Asha!
First of all, there is a new Geeta Dutt site (found thanks to a tip from Tom, formerly(?) Tommydan1).
And, I have been very happy to discover a comprehensive site on P. Susheela, whose wonderful voice can be found in many Tamil, Telugu, Malayalam, and Kannada films.
P.S. Also just discovered this site, which has a huge number of downloadable P. Susheela mp3s.