Merge clips _Impossible to edit from source monitor

Hi Neil, thanks for the answer.
Yes, I know the option Jeril Leirpool is pushing in his book,  but that doesn't solve the case.
OK, suppose I use "Create Multicam"  instead of Merge Clips, but it doesn't make me independent clips with pure sound from Lav microphones,

because while  editing  "Multicam sequence" clip , if I want to make a match frame on my sequence  I go back to the original  file with the original sound and that's bad ...

I would like to have independent clips synchronized with new  sound.
The interesting thing is the trick  when I make a couple  of these clips and then I go  in the console. (F12 ) I can select the option AllowMergedclipstobeopenedAsSequences  -true 

It's suddenly I can do Mark in on the all Merge Clips in the source monitor,

but if I want to create addtional  Merge Clips. once I've chosen AllowMergedclipstobeopenedAsSequences - true eariler 

then again an error occurs.
What's interesting is that these functions work in Avid, DaVinci Resolve and even in FCP7. The most important thing in this option is to create a new clip, which you use as a source clip withe the right sound combined.