Winamp stores a record in it's media library for each track on an album, so you can already create playlists containing just the track or tracks from an album that you want to hear.
There is an old plug-in, released in 2000, called "Gen Intro" (http://users.telenet.be/cr25996/waplugs.htm
) that may still work. Unless you're still using Windows XP, you may need to use administrator mode to install it and run Winamp once under administrator mode to configure it or change it's configuration. This plug-in allows you to specify which part of a song you want to hear (some of the start, some of the end, or some part in-between). However it will use the same specified part for each song in a playlist, instead of letting a different part be specified for each song in the playlist.
This plug-in was originally designed to allow playback of a brief part of the beginning of each song in a playlist, hence it's name__ Intro. It was later updated to allow any portion (instead of just the beginning) be played for each song in a playlist.