Database

[{"_id":{"$oid":"6242d36461e63768f0ac1529"},"id_z":10,"name":"Journalists","addres":"New York","workers":{"worker":[{"id_worker":15,"name":"example","job":"example","id_director":25,"hired":"2005-02-20","id_group":10},{"id_worker":16,"name":"example","job":"example","id_director":26,"hired":"2005-02-20","id_group":10}]}}]

Query

db.collection.aggregate([{"$project":{"workers.worker.id_group":0}}])

Result