Not on Aramex Global Shopper. Even on Flex I have a hard time getting combined shipping. The parcels have to arrive at Shanghai on the same day - it takes some very fine logistical juggling. Luckily Aramex has an office next to Shanghai Hongqiao, a slower airport in Shanghai. If sending to HK or JFK with a zillion flights a minute you can totally forget combining as your parcel will be off with the next batch and on that plane lickety-split.
If wanting to combine small items, try
www.postbox-courier.com.