Yes, this is usually done with backsounds--i.e., simply requesting that a particular sound file start playing when the question starts. You are correct that backsounds play to completion--but only until another backsound is encountered. This conveniently solves the problem of voice-overs running over because each question has its own. You do need to record the sound files yourself, but it's pretty easy. You can either type sndrec32.exe at the Run command on the Start menu to pull up Window's tape recorder, or you can download a nice freeware audio application like Audacity from www.download.com. The latter is a great application (especially for free!) that will allow you to pull up and edit your sound files with ease, and even convert them into MP3 or whatever format you like.

Hope that helps,
Blair