Cargo Nets

[B2C2]

Does anyone know if there is an STC or other method to add tie points and cargo nets to the interior of a 337? I am interested in setting up the plane for two front seat occupants, a couple of dogs and baggage and want to make sure the baggage/cargo is tied down properly. I'm currently removing a middle and aft seat for the dogs and this creates enough room for them. Id like to take out the other mid and aft seats and use that side of the plane for cargo, but may want other configurations as well. It seems like an arrangement that provides tie points in the ceiling and floor would permit this.