Connecting to multiple databases

[eluser]dave80[/eluser]
I know how to connect to multiple databases simulataneouly, with CI.
However my question here, is it possible to connect to different database.

For example a user/client logs in, via a common database, which containe ALL client ids.
Depending on this client id, a session variable is established with the database they belong to. Depending on that session variable, whatever query takes place, occurs in that specific database.

I hope this mad sense. I just dont see the sense in connecing to multiple databases, when they are over 100 clients which equals 100 db. (each client has their own database, with one generic db, that contains ALL user/id/pass and DB they belong to.)

Thank you for any replies