conditional write with multiple constraints

[simoami]

Hello,
I'd like to know if it's possible to use the overwrite flag with constraints on the hash key and 2 index attributes.

consider my model:

var UserModel = db.instance.define('user', {
  hashKey: 'id',
  schema: {
    id: db.instance.types.uuid(),
    cognitoId: Joi.string(),
    email: Joi.string()
  },
  indexes: [
    { hashKey: 'email', type: 'global', name: 'emailIndex' },
    { hashKey: 'cognitoId', type: 'global', name: 'cognitoIdIndex' }
  ],
  tableName: 'users'
});

Would User.create(user, {overwrite : false}, cb) be enough to prevent duplicate id, cognitoId and email? or do I need to explicitly construct an array of conditional expressions to cover all 3? Do perhaps I could redefine the model in a way that overwrite works?