Virtually all good ejector guns (exceptions being some cheap poorly designed one) have primary extraction to lift the hulls breaking them loose from the chambers for better ejection. What you are asking for is a gun with ejector timing such than you can stop the opening with the hulls clear of the standing breech, but the ejectors not yet tripped. Note that depending upon timing of the sears this may result in un-cocked hammers as well. In opening a double it is generally desirable to open it against the bbl check. There are much better solutions to the stated problem you mention than your suggestion, including ItalianSxS's suggestion.
