Dear Experts, Currently we have a Exchange 2010 SP2 Enterprise (2 HUB/CAS and 2 MB with CAS Array and DAG ) organization . Our plan is host one of our subsidiary companies mail boxes on our exchange organization. This should work like a small scale hosting .> 1. There is any possibility to implement two isolated GALs for these companies ? 2. Whats the best method to host two different companies in a single Exchange 2010 SP2 Enterprise organization? 3.In implementation stage we can expect any issues in current production ? Thanks in advance Regards CK

Hi CK, Prerequisites Set up Public DNS MX record for each SMTP domain for which you accept e-mail from the Internet. Each MX record should resolve to the Internet-facing server that receives e-mail for your organization.Send and Receive connectors should be configured, so that the Exchange organization can send e-mail to and receive e-mail from the Internet. Create Accepted Domains: New-AcceptedDomain -Name "domain1" -DomainName domain1.com -DomainType Authoritative Create Accepted Domains for every domains Now we need to configure the email address policy for the newly created authoritative domains: New-EmailAddressPolicy -Name EPolicyDomain1 -IncludedRecipients UserMailbox -ConditionalDepartment Recipient Container name -Priority 1 -EnabledEmailAddressTemplates SMTP:@domain1.com Apply the email address Policy: Update-EmailAddressPolicy -Identity EPolicyDomain1" Read here for implementing multiple GALs (GAL Segmentation): http://technet.microsoft.com/en-us/library/hh529948.aspxRegards from ExchangeOnline | Windows Administrator's forums