Switching DB Servers based on Query

[R P]

Hi,

I am trying to get MySQL Proxy to connect to 2 machines, say Server A and Server B.
If a query is querying a given schema, say X, it will go to Server B - otherwise, it will go to server A.

From reading other tutorials on switching the connection, I get that I have to set proxy.connection.backend_ndx to 1 or 2 depending on which server I want the query to go to, but that doesn't seem to work.
What is happening now is that I am connecting to one server, and the only time that it will switch to the other server is if I bring the db down on the first server.

This will all be done in a controlled environment - I can ignore cases where users execute "use X" or any type of transaction handling.

What step am I missing?

Thanks