Thanks for your response.
Problem is foreign keys. I know I can't create FKs to values in other databases (whether on the same server or not), which is why I'm asking, what would be considered best practice for this scenario?
Replication will only help in so far as I can ensure the lookup data is the same on all servers, but.......I lose the ability to apply foreign keys.
Server1 : MainDB, two smaller DBs. All require same lookup data
Server2 : (Different instance of) MainDB, three smaller DBs. All require same lookup data as above
Currently the lookup data is in the "MainDB" schema. Unless I copy it to the other schema I can't apply foreign keys.
So what do other people do in these situations?