ACTION: How to pull part of Title into Artist field

I have about 50 compilations where the Artist field has the Album name and the Tile and File Name are composed of Track - Artist.flac

So what I want to do is pull the Artist name out of the Title or File Name and into the Artist field with an Action but I'm not sure which one to use.

The formatting is the same on all of them.

Jump For Joy - Prince Francis
or
Jump For Joy - Prince Francis.flac

You could use the Converter "Filename - Tag" with the mask
%title% - %artist%
if the TITLE is fine and only the ARTIST should be filled with the data from the filename then use this mask:
%dummy% - %artist%

(there are also action to import tags from tags or to split tags into several tags - but as the converter has a preview function it may reassure you that you got the mask right)

Unfortunetly on about half of them the Title has the same data as the file name. Any idea how I can handle this?

Example
File name is: 01 - Jah Mike - Lovers Rock
Title is: Jah Mike - Lovers Rock

I want the file name to be 01 - Loves Rock and Artist to be Jah Mike

look it:
File name is: x1 - x2 - x3_
File name is: 01 - Jah Mike - Lovers Rock
Title is: Jah Mike - Lovers Rock
I want the file name to be 01 - Loves Rock and Artist to be Jah Mike
File name: x1 - x3__ x2
File name: 01 - Loves Rock___Jah Mike
File name: %title% - %artist% - %title%