Almost all of the major tags in JRMC are single value.
A bit of a pity if you are into classical music as you often have a couple of combinations like:
Gideon Kremer
Gideon Kremer/ Martha Argerich
Gideon Kremer/ Olaf Mustone
Harnoncourt / Gideon Kremer
Martha Argerich
Martha Argerich / Harnoncourt / Gideon Kremer
Etc.
You can use the People tag as being one of the few supporting multiple values but at the expense of having to update it manually each time you add new files.
There is a very elegant solution:
Create a field Artists

Set the Data Type to List
Set the Edit Type to Cannot Be Edited as it has no use to to edit a calculated field.
Press OK

Reopen this field
Check Calculated data and enter the following formula
[artist]&datatype=[list]
Press Ok
Use the standard tags to maintain your collection
Enter multiple artist and separate them by a ; (this is the standard)
Use Artists (individual) in your views where needed.
Thanks to Gappie
Want to see all people?
ListBuild(1,;,Replace([Composer],//,;),[Conductor],Replace([artist],//,;),Replace([Album Artist],//,;))&datatype=[list]
Simply combine all the fields you want using ListBuild.
If you have something like Jerry Leiber/ Mike Stoller/ Doc Pomus, use the Replace function to change the / into a ;

Using this formula you now get all the works Gidon Kremer is involved in.
Is there an easier way to obtain this?
Yes, type Gidon Kremer in the Search Box!
Most of the time the problem is spelling/conventions
For a computer Bing Crosby and Cosby, Bing are to different entities
I try to solve this by parsing the tags in such a way that each single word becomes an entry in the list:
ListBuild(1,;,Replace(Replace(Replace(Replace(Replace([Album Artist];[Artist];[Composer];[Conductor],//,;),/ ,;),/,),.),;;,;))&datatype=[list]
[Album Artist];[Artist];[Composer];[Conductor]
This concatenate the tags separated by the list delimiter
Then I replace all delimiters in this string like slashes, spaces, comma, etc by a ; to make it a list item (; is the separator for the list)
Now that I have all the words, I like to know where they originates from.
This one makes a list of all the names
Replace(Replace([Album Artist];[Artist];[Composer];[Conductor],//,;),;;,;)&datatype=[list]
Combine them in a view:
