Replacing in Title tags

Support
6

Your example strings have varying length and look like as they are following always the same pattern.
%TMP1% #%TMP2% %DUMMY% - %TMP3%. %DUMMY%
There are fix points in each string, so you can use an action "Guess values" to split the original title string into parts and save the valueable parts into temporary tag-fields.
Then assemble the new title string from the temporary tag-fields and put it in a temporary tag-field too.
If the results are looking good, then overwrite the tag-field TITLE with the newly calculated title value.
Afterwards remove the temporary helper tag-fields.

Here is an action group which has all steps included.

Begin Action Group Test_2012#20121114.MichaelZulu

Action #1
Actiontype 7: Import tag fields (guess values)
Source format __: %TITLE%
Guessing pattern: %TMP1% #%TMP2% %DUMMY% - %TMP3%. %DUMMY%

Action #2
Actiontype 5: Format value
Field ______: TMP4
Formatstring: %TMP1% #%TMP2% - %TMP3%

Action #3
Actiontype 5: Format value
Field ______: TITLE
Formatstring: %TMP4%

Action #4
Actiontype 9: Remove fields
Fields to remove (semicolon separated): TMP1;TMP2;TMP3;TMP4

End Action Group Test_2012#20121114.MichaelZulu (4 Actions)

You can also solve this task using the converter "Tag - Tag" and a regular expression function.

Convert | Tag - Tag | ALT+5

Select format string

Field:
TITLE

Format string:

$regexp(%TITLE%,'^(.+#\d+)\s.+(\s-\s\d+).+$','$1$2')

Preview
"Mozart P Con #6 In B Flat, K 238 - 3. Rondeau" ->
"Mozart P Con #6 - 3"

"Mozart P Con #7 In F For 2/3 Pianos, K 242, "Lodron" - 1. Allegro" ->
"Mozart P Con #7 - 1"

"Mozart P Con #7 In F For 2/3 Pianos, K 242, "Lodron" - 2. Adagio" ->
"Mozart P Con #7 - 2"

"Mozart P Con #7 In F For 2/3 Pianos, K 242, "Lodron" - 3. Rondeau" ->
"Mozart P Con #7 - 3"

"Mozart P Con #8 In C, K 246, "Lützow" - 1. Allegro Aperto" ->
"Mozart P Con #8 - 1"

DD.20121114.0840.CET