Is there a way to set-up for a one-time attribute to be added each time a product is ordered?

For example, we have large size artist frames that require additional shipping charges (based on speed of shipment) for *each* frame ordered. Right now, Zen Cart only adds in the attribute charge once - which is great if only one frame is ordered. However, if 2 or more frames were ordered than the attribute price should be multiplied accordingly and then added into the cart.

So, frame price is $15.90
attribute charge is $3.50 per frame

Thoughts?? Having issues on getting this set-up to work.