Transitioning mirrored DBs to an AlwaysOn Availability Group....same end point?

I have a SQL 2012 FCI that currently mirrors all of its DBs to a standalone SQL instance for on-site DR purposes, an instant-on server should something catastrophic happen to the main FCI if you will.  Currently these mirrored DBs are configured as synchronous but no automatic failover.  We want to add another SQL instance for off-site DR purposes.  Now obviously I can't mirror DBs to multiple instances without first transitioning to an AlwaysOn Availability Group first.  (The mirroring was initially set up under SQL 2008 and all servers later upgraded to SQL 2012, hence why an AG wasn't implemented from the get-go).  The idea is that we would first migrate the existing mirror server to a new on-site server configured as a secondary in an AG.  Once that is complete and the old mirror server decommissioned, we could then add another availability replica server located at the remote site.  The process sounds easy enough.

However, since these are mission-critical DBs, management doesn't want to lose the instant-on on-site mirror server without a replacement.  Obviously a DB can't be added to an AG if it is already being mirrored so something has to give.  Since mirroring is done on a per-DB basis, the mirroring can be removed from one database at a time and once gone, the DB can then be added to an AG.  I was stepping through this process and noticed that the AG wizard picks up the same endpoint already configured for mirroring (5022).  Can the same endpoint be used for both mirroring and availability groups at the same time?  It doesn't appear that you can add a new end point via the New AG wizard which would lead me to believe both mirroring and availability groups can co-exist on the same end point.  You couldn't have multiple mirroring end points in previous versions of SQL so I think its the same in 2012.  I was looking around and can't seem to find a definitive answer on this.  Can anyone confirm?