Loopback delete multiple relations

I'm trying to destroy multiple relations linked to a model from my angular application.

in my person.json I have two relations:

  "messageGroups": {
      "type": "hasMany",
      "model": "messageGroup"
    },
    "messageStudents": {
      "type": "hasMany",
      "model": "messageStudent"
    }

These work fine. However I want to delete multiple messageGroups and messageStudents for a person in one call. Rather than use multiple calls to Person.messageGroups.destroyById(...) and Person.messageStudents.destroyById(...)

My initial thought was to make a remote method in my person.js file that accepts a personId and an object containing ids for messageGroups and messageStudents.

But I'm unable to write working code. My last attempt looks like this:

Person.destroyTargetsFromMessage = function (personId, assignees, callback) {
        for(var i in assignees.studentIds){
            Person.messageStudents.destroyById({'id': personId, 'fk': assignees.studentIds[i]});
        }
        for(var i in assignees.groupIds){
            Person.messageGroups.destroyById({'id': personId, 'fk': assignees.groupIds[i]});
        }
        callback();
    };

Or would the proper way to do this use multiple calls to my API after all?

UPDATE

I've written this code that brings me closer to my goal:

Person.destroyTargetsFromMessage = function (personId, assignees, callback) {
        Person.findById(teacherId, function(err, targetPerson){
            for(var i in assignees.studentIds){
                targetPerson.messageStudents.findById(assignees.studentIds[i], function(err, student){
                    callback(null, student);
                    console.log(student);
                });
            }
            for(var i in assignees.groupIds){
                targetPerson.messageGroups.findById(assignees.groupIds[i], function(err, group){
                    callback(null, group);
                    console.log(group);
                });
            }
            callback();
        });
};

The only problem is that I cannot call destroyById on my targetPerson relations, but findById seems to be working just fine.

SOLVED

the method that deletes my relations is destroy, not destroyById

the method that deletes my relations is destroy, not destroyById