Need crossbar guidance improving pub-sub with RDBMS

hi, We want to improved an existing arch , where server is running crossbar.io and clients are running python-autobahn.
Clients are getting data via a stream and storing that data in a RDBMS. This setup works ok for apps with one server and one client, however we would like to host multiple client with multiple servers and we would like to have non repeating data stored in the RDBMS. my understanding is if there are many subscribers(clients) listening on same stream and all of them try to put the data in some database we will see multiple rows of same data. can you help me to find out if there is some functionality within crossbar or in general used within pub-sub arch which may solve this problem.

@oberstet @malibu @om26er