Multitrack File Swap

I am working in multitrack and I have two guest lines. I have grouped them, cut sections that need to be deleted, etc. The problem i'm having is this: I have two different recorded lines for one of the guests. I used the line that doesn't sound as good when I made these cuts and edits. How can i move the other wav file in, and keep the cuts and edits in place, and have those applied to the other wav file?

I know there's a way to do this, because when you can only find the multitrack session without the files, you can manually add the wav files you want to use. The problem is everytime I open the session, it opens it up with the original files. I hope this makes sense