Programmatically change PSMultiValueSpecifier values

Question

I have a setting bundle where I'd like to show list of Albums available in the gallery as PSMultiValueSpecifier type. I am done with most of the things with Settings Bundle but the challenge I am facing is updating settings bundle PSMultiValueSpecifier if new albums is added into gallery by user.

Can anyone shed some lights on it?

For reference you may check out livebooth application setting bundle Also find image at http://i.stack.imgur.com/2clIG.jpg for reference