Can I file a Motion to include the supplier of the subject product in the case?

No. A Motion to include the supplier of the subject product in the case is a prohibited pleading under Section 1 (g) of Department Administrative Order No. 7 Series of 2006. 

This however, does not prevent you from disclosing the name of the supplier of the seized non-conforming products which could be the basis for filing a separate administrative and/or criminal charge against the said supplier.