We have been knocked off (Branded but not a Patent-able item and no way to stop China if we did) and have noticed there are 6 ‘stores’ selling these items (at last count) - Curious if a China seller can reach into another China ‘sellers’ FBA to ship to a buyer? So are we dealing with 1 FBA inventory they are pulling from or each ‘store’ has its own inventory?
Just 1 example when heading down the listing to review who else is selling:
Interesting. I’m wondering if they can simply all drop ship from a main account with the FBA stock, or perhaps somehow use multi-channel to fulfill from one FBA inventory?
I’m really sorry this has happened @2005hateAmz.
BUMP for visibility 
Nope. FNSKUs are tied to the seller account/SKU/ASIN level. The only way is if they are co-mingled, but that still won’t give them more inventory than they sent in and it has to be the same exact UPC which won’t work for multiple listings either.
Short answer is no.