Merge Replication - help needed

Hi,
A client is currently running merge replication between two servers. The publication is only two tables but they use Automatic identity range support a column call ID which also hapens to be part of a composite key.
Now, the client has a new requirement to replicate the publisher database to a third server. But they do not want any changes for this third server replicating back to the publisher. Is there anyway of doing this? I cant use a different kind of replication because of the Identity range property! I cant un-check this column from the publication because it is part of the composite key.
Any ideas? all I can think of is trying log shipping, snapshot would be useful but it doesnt let you if you use Automatic Identity range support!
Cheers
Stewart