[{_id:"1",users:["1@abc.com","2@abc.com","3@def.com"]},{_id:"2",users:["1@abc.com","2@def.com","3@def.com"]}]

db.collection.update({users:{$regex:"(?:@abc\\.com)$"}},{$pull:{users:{$regex:"(?:@abc\\.com)$"}}},{multi:true})