[teleman2k1]

I have been using Mobilesheets for almosr a year now and I have over 1600 music pdfs built up. I was wondering if it is possible to add data into the custom field for multipe songs at once? I have more than 1 hymn book loaded , but when I started witn one book I just used the numbers of the hymns. Now that I have other hymn book, I would like to distinguish between tnem by using a couple of letters before the numbers. I don't want to have to do 1200 or so songs individually. I know that I can get a list of songs from companion, but I was wondering if that file can be edited and loaded back in?