Database
[{"data":[1,111]},{"data":[222,1]},{"data":[1,333]},{"data":[2,444]},{"data":[2,444]}]
Query
db.collection.aggregate([{"$match":{"data":2}},{"$unwind":{"path":"$data"}},{"$group":{"_id":2,"members":{"$addToSet":{"$cond":[{"$ne":["$data",2]},"$data","$$REMOVE"]}}}}])