Amazon Product

I have approximately 10,000 active SKUs. To date, I have uploaded around 4,500 on to Amazon. I would like to have someone else list the remainder. The vast majority of these products are already being sold on Amazon (some listed multiple times). I want these matched with the exisiting products, not listed as completely new items. For those few items that are not already listed on Amazon, I would like to have them set up with photos, descriptions, keywords, etc. taken from our website. We primarily sell items with size/color variations, and can have 100+ SKUs per product. I need to have these SKUs associated with a parent item, not simply sitting out by themselves. I would want a trial run on an item with a smallish number of SKUs before final agreement, to ensure that the work can be done to my satisfaction.