mysql to active record

Question

hi! having the following models,

Contact
has_many :group_contact_classifications
has_many :groups, :through => :group_contact_classifications

GroupContactClassification
belongs_to :group
belongs_to :contact

Group
has_many :group_contact_classifications
has_many :contacts, :through => :group_contact_classifications

i just want to convert the following mysql command to active record

SELECT *, GROUP_CONCAT(g.name SEPARATOR " ") AS grp_names
  FROM contacts
LEFT OUTER JOIN group_contact_classifications gcc ON gcc.contact_id = contacts.id
LEFT INNER JOIN groups g ON g.id = gcc.group_id
GROUP BY contacts.id
ORDER BY grp_names;

it's not

Contact.all
:select => 'id, group_concat(g.name separator " ") as grp_names',
:include => :groups,
:order => 'grp_names'

the error raised by mysql is Mysql::Error: Unknown column 'grp_names'

If you're wondering what I'm trying to achieve, I want to sort the contacts by the groups they belong to like the output of the sql statement above.

+------+-----------+
| id   | grp_names |
+------+-----------+
|  212 | Bar       | 
|  826 | Foo       | 
| 1310 | Foo       | 
| 2226 | Foo Bar   | 
+------+-----------+