Regular expression to split TITLE into WORK and PART

Mac
1

Having a bit of a blond time here:

I want to the TITLE tag from Qobuz downloads into WORK and PART tag.

The way the TITLE is formated is:
ie:
Cantata XYZ:Choral
Cantata XYZ:Aria1
etc...
Anything before ":" should move into WORK tag, anything that follows ":" should go into PART.

Should be really easy but I fail.... Thanks for any hints.

2

Have a look at the documentation about actions for the Mac:
I would use an action of the type "Import tag fields"
Source: %title%
Target: %work%:%part%

3

Many thanks. I kew it must be simple... That did the trick.