You can create a Public Contacts folder that can be used in IMail (no Outlook or Collaboration WorkGroupShare required).
To create contacts:
Example:
Sam - SSmith@yahoo.com,Josie - jbrown@hotmail.com,HumanResources - hr@ipswitch.com
To create a Public Contacts folder for a non-primary domain follow the steps 1 - 3 above. Create a "Web" folder within the non-primary domain. Add the new config_CommonAddrBook.cgi file in the new "web" directory.