Is there any way to mask the INBOX label for Dovecot 1.2x Shared Mailboxes?

I'm setting up a new Dovecot sever to replace an old Cyrus server, and need to keep things as consistent as possible. I have a couple local accounts, like junkmail and notjunkmail that users get shared access to, and can drop things in to train sa-update. However, when users share over junkmail's inbox, it's displayed in the hierarchy:

• Other Users
  • junkmail
    • INBOX

Is there any way to get junkmail's INBOX to just show up at Other Users/junkmail and not require that extra depth?

• Other Users
  • junkmail

I'm running Debian Squeeze and the standard dovecot package available therein:

# uname -a
Linux internet.digitalquay.com.au 2.6.32-5-xen-amd64 #1 SMP Sun Sep 23 13:49:30 UTC 2012 x86_64 GNU/Linux
#dovecot --version
1.2.15

I'm running in a configuration where all mail is owned by the vmail user, due to the impression I'm under that it's a better way if there are shared mailboxes.

Relevant bits of dovecot -n:

mail_uid: vmail
mail_gid: vmail
mail_location: maildir:/var/spool/dovecot/user/%u
mail_plugins: acl imap_acl
namespace:
  type: private
  separator: /
  inbox: yes
  list: yes
  subscriptions: yes
namespace:
  type: shared
  separator: /
  prefix: Other Users/%%u/
  location: maildir:/var/spool/dovecot/user/%%u:INDEX="/var/spool/dovecot/user/%u/Other\ Users/%%u"
  list: children
auth default:
  passdb:
    driver: ldap
    args: /etc/dovecot/dovecot-ldap.conf
  userdb:
    driver: passwd
    args: uid=vmail gid=vmail blocking=yes mail=maildir:/var/spool/dovecot/user/%u

Am I barking up the wrong tree, or is this possible?