Yes.
Appending a field with a fixed or variable information is even answered in the FAQs.
/t/967/1
Only that you set " - (%artist%)" instead of "xyz".
I am not quite sure what you mean with your second formatting:
"FakeSongTitle" by "FakeArtist" becomes "FakeSongTitle - (FakeArtist)" by "Various"?
Which part is new? What do the inverted commas mean?
What is a "Fakesongtitle"?
Could you give a concrete example of the before and after?