select.php

<?php        
        $following = $this->Strategies->Users
            ->matching(
                'FollowingAgencies.Employees'
            )
            ->where(['Users.id' => $this->Auth->user('id')])->toArray();

        $following = Hash::extract($following, '{n}._matchingData.Employees.id');

        $query = $this->Strategies->find('open')
            ->order(['Strategies.created DESC'])
            ->contain([
                'Users.Agencies',
                'Assisting' => function ($q){
                    return $q->order(['Assisting.last_name ASC', 'Assisting.first_name ASC']);
                }])
            ->where(['Strategies.user_id IN' => $following]);