Като това
Contacts.aggregate( [
{ $group: { "_id": { name: "$name", city: "$city", state: "$state" } } },
{ $project: {_id: 0, name: '$_id.name', city: '$_id.city', state: '$_id.state'} },
{ $sort: { AgencyTranslation: 1 } },
{ $limit: req.query.limit | limit }
], function () {
});