We have 2 child domains each containing Exchange 2007. The global address list is populated with contact details of users from both child domains. I want to change this so that the GAL in child domain 1 can only see users from child domain 1, and the GAL in child domain 2 only shows users from child domain 2. I found a link explaining how to create a custom address list, add certain users, and set permissions via ADSIedit to deny a certain group. But I feel their must be a better way to do this. I dont want the extra admin of adding users to custom address lists every time I create a new user. Thanks for any suggestions.

The method that you have outlined (Address List Segregation) is the only way to do what you want, with all the work that it is required. Exchange operates at the Forest level and expects that everyone in the Forest will want to see everyone else. It doesn't care about the domains within the forest, those are just containers for users. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

Darn! Thanks for letting me know Simon.

you can follow the OPTION 2 in the whitepaper below. that matched your domain set up http://technet.microsoft.com/en-us/library/bb936719(EXCHG.80).aspxDhruv