Exchange 2010: Mounting a passive copy while DB is in use and Circular logging enabled

Hi

We shut down all our servers before the storm hit North east USA.  We have an exchange 2010 DAG in place and 6 mailbox servers with circular logging enabled (waiting on the backup solution implementation; that is why). 

Now that servers are rebooted; one of the mailbox servers is holding all the active copies.  I want to activate some of the DBs on other mailbox servers. 

Can I do that while users are connected?  Our users use outlook 2003, 2010, owa and active sync.

I am afraid that if I do so they will get a pop-up about being disconnected.

Thanks