Question : Sharing GALS between 2 disjoint exchange organisations

Dear Experts,

My company has recently acquired another company.
The two companies have totally separate domains , exchange organisation and networks, etc.
The parent company is running running  Exchange 2003 on a Windows 2000 domain whilst the acquired company has Exchange 2003 on a Windows 2008 domain.

We would like the GAL of the parent be available on the acquired companys' GAL and vice versa ?
I understand we may have to manually Export/import the contacts between the two comapnies every month.

My question is more around how we make the imported/exported GALs  available to users.

 

What would be the best way of going about this?

Answer : Sharing GALS between 2 disjoint exchange organisations

Micrsoft created something to solve this: Microsoft Identity Integration Feature Pack.
 
http://www.microsoft.com/downloads/details.aspx?FamilyID=d9143610-c04d-41c4-b7ea-6f56819769d5&displaylang=en

It does exactly what you're looking for. Here's a good walk-thru:

http://www.msexchange.org/tutorials/GAL-Sync-Identity-Integration-Feature-Pack-IIFP.html

Unfortuntely, its not the most intuitive thing, but it works! It creates Contacts in the target OU of the target Domain for Users, Groups and Contacts in the Source domain, and vice-versa.