Assuming the prerequisite tags are properly formatted, the virtual tag formulas you provided should actually work!
To be clear, what I mean is that, if entered into a virtual tag formula
1/ <Artist> - <Title> - <Track#> - <Album>
2/ <Artist> - <Title> - <Album>
3/ <Artist> - <Title>
will take the tags that you're requesting and combine them into one tag, separated by hyphens. Here's an example of the first one implemented in the virtual tag editor:
This is an interesting problem, so I'm happy to keep helping. Any more details about how your stuff is formatted and exactly what you'd like out?