How can this be a Eloquent collection, with it's relations

I have a DB statement,

return DB::select('select *, SUM(`unrestrict`), SUM(`quarantine`) from n.stock_levels_crm GROUP BY `mat_no` ORDER BY `mat_no` ASC');

How can I load relations on top of this, as a model. (the model is called "Stock_Levels"

I think the right way to do it is

return Stock_Levels_CRM::with('materialDescription')->select(DB::raw('*, SUM(`unrestrict`), SUM(`quarantine`)')->groupBy('mat_no')->get();

But if I do it this way the whole thing just crashes and times out

Thank you

via Chebli Mohamed