Attaching a picture of an idea on Exchange configuration. Basically we need the following, Forest 1 email to specific people or groups in Forest 2, cannot see or email people in Forest 3. Forest 2 can email to Forest 1 specific people or groups, Can email to Forest 3. Forest 3 can not see or email people in Forest 1, can email people in Forest 2. I know we need to do filtering. Question is can a separate Forest 4 that handle all the filtering? Do we need to trust setup between them? Can we just use an Edge server? I am familiar with basic exchange setup and config.

If anyone has any better suggestions on configuration. Maybe doing away with Forest 4 and doing direct links? Thanks.

Hi How about using linked mailboxes. Forest 1,2,3 store the usermailbox, and Forest 4 store User Accounts http://technet.microsoft.com/en-us/library/aa998031.aspx Deploy Exchange 2013 in an Exchange Resource Forest Topology Cheers If you have any feedback on our support, please click here Zi Feng TechNet Community Support

Hi How about using linked mailboxes. Forest 1,2,3 store the usermailbox, and Forest 4 store User Accounts http://technet.microsoft.com/en-us/library/aa998031.aspx Deploy Exchange 2013 in an Exchange Resource Forest Topology Cheers If you have any feedback on our support, please click here Zi Feng TechNet Community Support