Case Conversion script for Artist name with 3 letters only

When using Case Conversion (Mixed Cases) how do you add in the (word begins and end) section to include artist with 3 letters to be Capitalized:

Example:

Abc
Tlc

Should be:

ABC
TLC

I think you should try the Replace action for this:

Action type: Replace
Field: ARTIST
Original: Abc
Replace with: ABC

[x] only as whole word

[x] case-sensitive comparison

There ist a tricky bit: how is MP3tag to know that a 3-letter combination is to be capitalized whereas the rest is not. E.g the Group "The The" would become THE THE which I would not like.
No: you could do the following:
Add a column "Artistlength" with the contents $len(%artist%) and then sort or filter by this length, select only those which are short enough and apply the case conversion "capitals".