Based on your database structure, it looks like you have the schema for a many to many relationship already setup.
On your object model, your customerManagers method should return the result of a call the belongsToMany method. Since the name of your pivot table deviates from what Eloquent expects, you can pass it as a second argument in the belongsToMany call.
public function customerManagers()
{
return $this->belongsToMany('App\Users', 'objects_customer_managers');
}
As outlined in the docs, you can add a similar method on your users model to perform the reverse.
Now you can get the objects customer managers by calling the customerManagers method defined on your object model.
$object->customerManagers()->get();