Numbering group of titles independently from tracknumber

Hi at all!
I'm using mp3tag to tag my flacs. Until now everything worked fine and I could solve most of my problems/wishes by trying or searching.

But now, I think I've reached my limits (for the moment):

I have an audio book and chapters are between 8-13 single files. Of course I can distinguish them by adding the tracknumber, but I'd like to add individual numbering for each single chapter.

Right now if only considering the title column, I have this

Chapter A
Chapter A
Chapter A
Chapter A
Chapter A
Chapter B
Chapter B
Chapter B
Chapter B
Chapter B
Chapter B

It should look like this:

Chapter A (01)
Chapter A (02)
...
Chapter A (11)
Chapter B (01)
Chapter B (02)
...
Chapter B (13)
...
Chapter Z (10)

Is there any possibilty to do this with a function?

Would be great if anyone can explain what is possible or what a possible workaround could look like.

Thanks!

One solution could be:
Just mark the "groups" of chapters and then use the Tracknumber Assistant "CTRL-K".

This could be a solution, however it is uncomfortable and would mean double work as well. For better understanding:

The whole audiobooks already contains right tracknumbers from 1 to end. e.g.:

Chapter A - Tracknumber 001
Chapter A - Tracknumber 002
Chapter A - Tracknumber 003
...
Chapter B - Tracknumber 011
Chapter B - Tracknumber 012
Chapter B - Tracknumber 013
...
Chapter Z - Tracknumber 134

Action: Format Value
Field: TITLE (I think, you're not clear about that)
Formatstring: %title% ($num(%_counter%,2))

BUT: you have to do this for every chapter separately because there is no way to reset the counter.

Solution 2:

  1. Step: Put each chapter in an extra folder:
    Tag - Filename Converter: %title%\%_filename%

  2. Step: Give new tracknumbers with the Autonumbering Wizard:
    choose "Leading zeros for tracknumbers" and "Reset counter for each directory"

  3. Step: Put the new tracknumber into the title:
    Action: Format Value
    Field: TITLE
    Formatstring: %title% (%track%)

  4. Step: Put the files back to the original folder:
    Action: Format Value
    Field: _DIRECTORY
    Formatstring: .\

  5. Step: Use the Autonumbering Wizard again to restore the old tracknumbers.

pone, das ist clever - oder sagt man cool?

DD.20110115.1843.CET