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rfog - major re-development of the calibre viewer is currently underway as part of calibre version 3. The major thrust of version 3 is to address the issues with 'shared libraries' to which you allude.
So it is improbable that the current viewer will be enhanced a) because it's on it's deathbed, and b) especially not in a manner that might encourage the 'misuse' of version 2.
If you
Set up a calibre development environment then I understand its possible to preview what's coming in calibre 3.
BR