I am new to exchange so please bare with me. I have 2 seperate companies Company A and Company B, which have nothing to do with each other. The only common thread is that I must host both of them on a single exchange server? Can this be done? Is it a good idea? These are two different companies so they must not be able to see the others companies tasks, calendar, etc... Any direction would be great. Thanks, Kris

Exchange Servers are installed into what is called an Organization. There can only be 1 Exchange Organization in any givenForest. What you can do is to install 1 Exchange Organization in a separate Forest, i.e. Resource Forest and provision it for both companies. Mind you this is both difficult and an administratively more costly solution than to have 2 single Exchange Organizations; one in Company A and one in Comapny B. <Company As Forest> <Resource Forest> <Company Bs Forest> To make the other companys addressbook and calendar items hidden is a bit tricky but Microsoft has recently published a White Paper on this topic: White Paper: Configuring Virtual Organizations and Address List Segregation in Exchange 2007