Why aren't you doing your MC stuff in the project bin to begin with? That's where you should.
In fact, you can have a bin with say 10 clips of different scenes, each one with an accompanying separate audio file. Select all 20 items, right-click/Create Multicam, and you'll have 10 multicam clips essentially from all twenty items.
Multicam is the proper way to join video & separate audio for nearly everything. Merge clips is simply for quick timeline stuff, say you want to set a music track with a video clip so you can move them together right now.