Dinamically create connection pool

I have a service that uses a seperate database for each client, so we currently create a new connection pool on glassfish for each client, so I'd like to create a connection pool "on the fly" if one does not exists, keep this connection in memory for a specific time and then remove it after it times out. We have considered removing the pool all togheter and just connecting to the database for every connection, but we really like the advantages of polling connections.

I have seen (and tested) something similar on tomcat, is this possible?? any other ideas??

thanks in advance

Jose Suero