Mosquitto Secure MQTT connection

Question

My Question is regarding TLS/SSL MQTT connection. I've installed moaquitto broker from this website.

http://www.eclipse.org/mosquitto/download/

and done with simple subscribe/publish using paho eclipse library in java. then I created X509 certificates using bouncycastle in java. but now I am stuck at server configurations regarding these certificates.I need to use different certificates for different topics on same broker. What I found is the following mosquitto-auth-plug.

https://github.com/jpmens/mosquitto-auth-plug

But here in mosquitto_auth_plugin we need to define backend databases holding username and password for authentication. How can we save certificates here? as I stated above I am creating X509 rootCA for server and X509 certificates for client.I am quit confused about it.

Is there any other/better way to acknowledge server regarding these certificates? Can this purpose be achieved using anyother broker like HiveMQ,ActiveMQ or RabbitMQ?