Format value of split fields

I am trying to format the field "MOOD" by using the following statement:

$if2(%MOOD%,%TONES%)

After that I split the field "MOOD" into separate values with another action.

This works fine when the field "MOOD" is empty but if MOOD already contains a value only the first of the MOOD fields is kept.

I have trouble finding a statement that only copies the TONES field to the "MOOD" field when no "MOOD" fields exist (or they are empty) so that existing "MOOD" fields aren't overwritten or removed.

Does anybody know a solution?

I would not use a $if() function but
an action of the type "Format value" for MOOD
Format string: $meta_sep(mood,\\)\\%tones%
The double backslash indicates for MP3tag to create a multi-value field.

Thanks for your reply. Your solution works perfectly and combines 2 actions into one so it is more efficient too :grinning: