Tag Tracks With Multiple Artists

Basically, you are right. But: if you start using a unique separator that exclusively separates the band names from the contributing artists, then it would be much easier to replace that separator with the then standard one.
Otherwise you would have to check each entry for artists individually to replace the correct delimiter.
In the case of

it would always be the ;, not the comma, not the ampersand.
Should be easy to replace, IMHO.