Does anyone have any systems that integrate to NetSuite with multi book accounting enabled and are able to sync data to the adjustment book?

Edited, more context below.

Oh interesting - so the adjustment book is actually a subsidiary? For more context we are looking to sync expenses from Concur into the adjustment book

To be honest, the account I did that on was very customised, it depends on what your setup is but generally you can post Journal Entries to an adjustment book in a similar way you would post to the primary book via the integration; you would need the adjustment book ID, and the ID of the subsidiary you're posting the adjustment to. What's the use-case for putting Concur data into the adjustment book? Surely expenses from Concur would go to your primary book?