Question : Microsoft, Exchange, 2007, default global address list

I understand you can't delete this llist but I've created a new one. How do I make this the default? Or can I?

Answer : Microsoft, Exchange, 2007, default global address list

You can't remove the default GAL; however, you can restrict access to it.....

Take a peek at this Microsoft article:
http://technet.microsoft.com/en-us/library/bb936719.aspx#ResAccDefGAddList


Also, I've bookmarked the following article in the past but never implemented it:
http://telnetport25.wordpress.com/2008/06/04/exchange-2007-service-pack1-and=-address-list-segregation-part-1-getting-started/

That article might not fit your scenario, but it does provide a way to segregate multiple GALs.  I really can't offer advice on this one.....I've never tried it.