Migrate exchange public folders between different domains

We are in the middle of our migration. For various reasons we have two domains, one NT and one 2003. On the NT domain is Exchange Server 5.5 and the 2003 domain has Exchange Server 2003.

I would like to migrate our public folders from 5.5 to 2003. I have been looking at the knowledgebase articles http://support.microsoft.com/kb/843107 and http://support.microsoft.com/kb/822895 In the first article under the /SC option there is a phrase, “A typical add operation requires that both the source server and the destination server be in the same routing group.” Does this mean I can’t migrate between domains? What is a routing group?

Any help is appreciated. Thanx