[Dovecot] recipient_delimiter

[LuKreme]

Can I enable $recipient_delimiter = ‘+’ for only the virtual sql users?

$ doveconf -n
# 2.2.5: /usr/local/etc/dovecot/dovecot.conf
# OS: FreeBSD 9.1-RELEASE i386  
auth_mechanisms = PLAIN LOGIN
disable_plaintext_auth = no
first_valid_uid = 89
login_log_format_elements = user=<%u> %r %m %c
mail_location = maildir:~/Maildir
mail_max_userip_connections = 90
managesieve_notify_capability = mailto
managesieve_sieve_capability = fileinto reject envelope encoded-character vacation subaddress comparator-i;ascii-numeric relational regex imap4flags copy include variables body enotify environment mailbox date ihave
namespace inbox {
  inbox = yes
  location = 
  mailbox Drafts {
    special_use = \Drafts
  }
  mailbox Junk {
    auto = subscribe
    special_use = \Junk
  }
  mailbox NotJunk {
    auto = subscribe
  }
  mailbox Sent {
    special_use = \Sent
  }
  mailbox "Sent Messages" {
    special_use = \Sent
  }
  mailbox Trash {
    special_use = \Trash
  }
  prefix = 
}
passdb {
  driver = pam
}
passdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  driver = sql
}
protocols = imap sieve
service auth {
  unix_listener /var/spool/postfix/private/auth {
    mode = 0666
  }
}
service imap-login {
  inet_listener imaps {
    port = 993
    ssl = yes
  }
}
ssl_cert = </etc/ssl/certs/dovecot.pem
ssl_key = </etc/ssl/private/dovecot.pem
userdb {
  driver = passwd
}
userdb {
  args = /etc/dovecot/dovecot-sql.conf.ext
  default_fields = uid=vpopmail gid=vchkpw mail_location=/usr/local/virtual/%u mail=maildir:/usr/local/virtual/%u
  driver = sql
}
===

My pam users all have .procmailrc, and I do not want to interfere with those.