Advice for shipping parts from the US to a vendor in China?

Hello all, I’d be grateful for some advice.

I work with a number of manufacturers in China. Generally they’re the ones shipping things to me, and that will usually go off without a hitch. Every once in a while though, I need to ship some parts to them. Perhaps a sample part, or subcomponents that I’d like them to integrate into a larger product.

These are small shipments - usually just one small box via DHL, FedEx or UPS, with a customs value under $1000. Unfortunately, they usually run into delays in customs, and then my vendor will have to go to the trouble of paying the duty and billing me for it.

I’m happy to pay the duty, but I’d prefer not to inconvenience my vendor with the whole process.

Does anyone have any advice for an easier way to make this work? For example, can I pay a company in China to receive the package and handle all the customs and duties, and then ship it via a domestic carrier to my vendor?