HASHLOV is exactly what you would use in this situation. Since a hash is deterministic (same input always equals same output) the hash function will create the same index into your seed list. So, as long as the same seed list is being used for both databases, you will get the same result.
The only caution here is that you want to make sure that both DBs are storing the data the same way. If one of the DBs pads a field with spaces, or if they are not stored in the same case, they will not hash the same. i.e "Bob" is different from "Bob " is different from "BOB".