What you are asking about is 'multicam editing'. Final Cut Pro has this ability built in for up to 16 angles of real-time playback. It can be done with a little extra work in Final Cut Express for $199.
To do it in iMovie would be tricky and time consuming. I think I'd import the video to two different events to keep them separated. I'd then review each to get a feeling of where the scene of interest are and the angles, and I write down any hints. I'd then hi-lite the scene in the event and drag it to the single project in order of interest. After building all of those up, I'd have another project with the video of the audio of interest and export that audio, then bring it into the project, perhaps as background audio, or attached to the first scene. I think you'd have to import it into iTunes first. Then use the precision editor to match the video to the audio.
