Swarnalatha vs Madhushree

Hey, guys. Madhushree and Swarnalatha have closely worked with ARR. I, however, always get confused between their voices. Do any of you feel the same?

Here's a sample video of the two singers.

[YOUTUBE]http://www.youtube.com/watch?v=yEIKdvQ28IE[/YOUTUBE]
[YOUTUBE]http://www.youtube.com/watch?v=IxqB1xUX36s[/YOUTUBE]

Both are amazing and similar. I have heard many more songs by Madhushree so I can tell them apart. My favourite vocal performance by her is this largely unknown song from 2009:

Wow! They ARE similar after all. Good lord! Is there a specific pattern to recognize their voices or tell them apart? I can tell Dola Dola was sung by Swarnalatha. That's something I was able to tell apart.