removing long words from mp3-titles

I have a problem that I cannot figure out how to solve - and I cannot seem to find relevant information neither in FAQ or in the help-section.

I have hundreds of educational files that I listen to on my ipod. My problem is the long titles - it's difficult to find the relevant titles on ipod, because only the first 20 letters or so are showed - and the first letters are all almost alike.

All the titles start with numbers, after that they all have a long title such as: dialogue mp3 - lessons - "and then the relevant title.
I want to remove not the number but the "dialogue mp3 - lessons -" section
Example:I want title changed from "622 dialogue mp3 - lessons - xxxxxxxx" to "622 xxxxxxx". How do I actually do that - I'm afraid I simply don't understand the 'string' information as I not a computer nerd.

Can you help?

It looks to me as though you always want to get rid of the (string!) constant "dialogue mp3 - lessons - "
So use an action of the type "Replace" on the field TITLE
Search string: dialogue mp3 - lessons -
Replace string:
(leave empty)