How to add an author to a book written by siblings with the same surname?

[Addy]

I'm trying to add the sister of this book as an author:
https://www.goodreads.com/book/show/4...

They both have the same surname and it seems the system doesn't like it very much. I tried adding spacing between the names of the second sister, but it didn't help. Can someone add the author "Shawnelle Gibbs" to the list of authors? Or is that not possible?

Thanks!

[Scott]

The system won't let you add a name if it seems too similar to the one that is there. To get around this you can enter something that is more different and then edit it afterwards.

I have added her name to this book.

[lethe]

If the names are too similar, the system refuses to add the second name.

One workaround can be found here: https://www.goodreads.com/topic/show/...

[Addy]

Thanks everyone! ^_^