Hello.
I have been looking for a solution for this too and I found out today how to do it in Band in a Box 2025 for Windows (I'm not sure if this is available in other versions).
I know this is a very old conversation but I think it makes sense to indicate what I found today for completing this conversation in case somebody else is looking for a similar solution.
What I found is that in Band in a Box 2025 for Windows (not sure if also in other versions), there are functions to do a "Special Copy" from the song to the clipboard and a "Special Paste" from the clipboard to the song. They allow a number of different features to be exported and imported to the clipboard or to a text file.
In this particular example, I want to enter a few chords from a text file. For that, I've created the following text based on the format that it uses when using "Special Copy"
[Chords]
|a) C|Dm|F|G|C|Dm|F|G|b) C|Dm|F|G|C|Dm|F|G|
[ChordsEnd]
This is the process I used to import those chords:
[list]
[*] I've created a new song
[*] Copied normally the text above to the clipboard with the chords (including the [Chords] and [ChordsEnds] delimiters)
[*] In Band in a Box, menu Edit --> Paste Special (from Clipboard Text to Song)
[*] You will see a dialog allowing you to paste the information in different ways. I've just clicked "OK" without modifying anything.
[*] Then in the song I could see the chords as expected.
I hope it helps. It seems that you can even indicate a) b) etc, to indicate changes in the substyle, etc.