From one account to another, no. However, since these are not DRM protected you can send them from your computer to each Kindle's unique email address.

To do so, go to the Manage Your Devices page for each account and lookup the unique email address listed beside each Kindle. From your PC/Mac send the book via email to each Kindle using the email address that Amazon has assigned to it.

This process will actually turn book into what Amazon calls a Personal Document, in this case in two different Kindle accounts. The book is now stored in the Cloud for each account and each account can download it from the Cloud to any other registered device within that account.