"Friendship bound them together" is less colloquial and more expressive then "they're friends". It has nothing to do with a failed marriage or "let's stay friends" after a break up.
Though, I'm not fluent in English, so might be wrong.
< since that would require a lot more manual labor>
That's. Lots of manual labour is the main problem of the initial task given by Ricardo 14. Perhaps some software could make the task easier, but it's needed to be written before.
Actually, I've tried to do that using this site: http://www.englishprofile.org/
It turned out to be not an easy task, because most work have to be done manually. If you have any ideas how to make it easier, please tell.
If you have time, please take a look at these English sentences added by user Astink who is now inactive, thus the sentences are available for adoption: https://tatoeba.org/eng/activit..._of/astynk/eng
They're all translations from Russian. If you have any questions feel free to ask me. Thanks!