[Dovecot] Direct groups of users to pairs of backend servers

[Murray Trainer]

Hi All,

I am using dovecot in the Director setup with multiple proxy and
backend mailstores and user information stored in LDAP.  I am aware
users can be directed to a single backend server.  It would be useful
to be able to direct groups of users to pairs of backend servers to
give some fault tolerance against NFS issues and make the whole thing
more scalable.    Otherwise each backend mailstore will need all
the NFS mounts and the whole cluster will be affected if one NFS mount
has an issue.  I am not sure if this possible with the current
dovecot implementation?  If not it would be a great enhancement.

Thanks

Murray