I have a customer with the above scenario. They are currently only using Laserfiche in domain "b.company.com", but have people in the other domains that need to be given access. I find very little documentation about how to set up AD users in multiple domains.
I know that in LFDS, I would register a new identity provider for each domain (providing credentials for given domain) and that LFDS must be able to contact a Domain Controller for each of the domains. But is that enough? When a user from another domain tries to log into the repository in Domain B, does LFS need access to their DC to authenticate them or is that all handled by LFDS?