I guess I should elaborate...I agree, Matomart may be set in their shipping, but if orders were combined, they might be able to consolidate packaging and that may lead to a reduction in shipping.
I was thinking more like distributors of accessories like Aber, Atak, even Shapeways; along those lines.
I’m in a Mazdaspeed group and we often had group buys of things like air intakes, downpipes and some other big and small items and between shipping and customs we saved a bit.
Just an idea...