The first issue is the a FMS cannot connect to another FMS server, even of the same version. You can install the client ODBC driver and set up the DNS on one machine and it seems to connect to the other FMS so that you could access the other one's data via an ODBC import. The problem becomes the inability to pass credentials. So you can almost make it happen, but then you get a prompt for User ID and password and it won't import via ODBC import. I've heard rumors that if you set up an auto login account or no credentials, it may work. But I've never had a database I wanted to accessed without security.
What this boils down to is doing text exports and manual imports from a folder that both servers can see. It is not elegant, but can be made to work. Or the other alternative is to do everything in a FMP client because a FMP client can see both servers at the same time.
I've put in a suggestion that FileMaker allows an FMS to see another FMS and validate credentials and put table occurrences of data from the other server in the first server. There are many times this would be useful.
FM11Server need Advanced edition for ODBC.
And ODBC may be slower then text importing, not support repeating field.