Just in the event you are waiting to get your project going, I'll offer a more generic answer as I don't use vers. 7 You would simply unlink the video from the audio on the timeline ( I think right clicking will bring up that menu) then cut the video where you want it to stop, leaving the audio untouched. You could add a video fade also if you like.
I'm sure the folks who use this vers will offer a more specific step by step when they come by, this may get ya going though.
That's how I'd do it, too.
Another option might be to just plop the montage on Track 2 at the appropriate starting point and not do anything with Track 1 (the guy singing). The video from Track 2 would be used instead of the Track 1.
Not sure what would happen with the sound though - don't remember if Track 2 audio overlays Track 1 or if they get mixed
Also not sure what the OP wants... is the guy singing supposed to be "background" as in you can still hear the montage audio with the singing as light background, or whether the guy singing is the *only* audio.
What Ed's describing is called an L-cut, a popular technique that I describe and illustrate in my books on Premiere Elements.
You simply lower sound level or remove the audio from the cut-away clips and place them on Video 2, overlapping some of the video (and audio) of the singing guy, on Video 1.
And was I right that, by default, video on higher tracks overlays lower tracks, while audio from all tracks is mixed together?
On the nose, Ed!
Another, very similar method is to Alt-click on the Video to unlink it, then edit as desired. Either way will work. The Alt-click is more temporary, but if one were to, say reset the Out Point, by Click-dragging on the Tail of the Video, it would do all that is needed. If one did this, and did not want anything else on the Video Track to move, they would hold down Ctrl, while Click-dragging (just the opposite of how it works in PrPro).
One can also Alt-click on the Audio portion of a Clip, should they wish to edit it independently from the Video.
Personally, I find the use of both the L and J-cuts lacking in most non-Hollywood edits. There, we see/hear them all of the time, and do not really take notice of them. They go a very long way to establishing a change in time and/or place with the audience
Imagine an actor having a telephone conversation. We see him and hear the conversation. The conversation continues, but we now see someone driving toward the actor's house. The audience now knows that these two events are happening simultaneously, but in slightly different locations.
BTW the L and J-cuts are just the opposite of each other, and get their name from how the footage looks on the Timeline, like the letter L, or the letter J.