Try this....
Snelgrove designed a piece of equipment called a Snelgrove Board (the coincidences never cease!). A Snelgrove Board (SgB) is a piece of equipment very much like an inner cover with a few "extras".
Rather than a hole in the center of an inner cover, the SgB has a much larger opening that is double screened, hence a SgB is sometimes referred to as a double screen board.
Additionally, a SgB has entrances on three sides of the board on both top and bottom (six in total). The side with no entrances is the front of the board.
For later discussion imaging that the top entrances are numbered 1, 3 and 5 for the right, back and left entrances and the bottom entrances are numbered 2, 4 and 6 for the right, back and left respectively.
Towards the beginning of swarming season a SgB is used in combination with a queen excluder and hive manipulations on a double brood chamber colony to simulate a swarm while keeping both the parent population and swarming population combined at the same location!
How is this possible?
The hive manipulations consist of segregating the brood frames so those with eggs, larvae and brood are moved to the top hive body and empty frames are segregated to the lower body.
This is another technique that hinges on finding the queen. When she is found she is moved to the lower brood chamber on a frame of eggs, larvae and unsealed brood. This should be the only frame in the lower brood chamber with any stages of brood - all other frames in the lower brood chamber should be empty or contain only stores (pollen, nectar and honey).
Above the bottom brood chamber go a queen excluder, super(s), and the top brood chamber containing occupied brood frames.
Three days later the super(s) will be occupied and the nurse bees will have passed through the queen excluder to the brood frames in the top chamber.
At this point in time the SgB is inserted with entrance 1 open - all other entrances on the SgB are closed. For the next few days, field bees from the top brood chamber will exit through entrance 1 and join the population below the SgB by using the original front entrance.
One week after the initial manipulation the beekeeper closes entrance 1 and opens entrances 2 and 5. Thus, the bees from the top brood chamber that "graduated" to field bees return to and reinforce the lower population by using entrance 2.
During the next week the top brood chamber bees that become field bees will get accustomed to using entrance 5. While the bees in the lower chamber use either the original front entrance or entrance 2.
At the end of the second week the beekeeper closes entrances 2 and 5 and opens entrances 3 and 6. Again the top brood chamber field bees reinforce the lower population by returning to the left hand lower entrance (entrance 6) and the top back entrance (entrance 3) becomes the top brood chamber's main entrance.
By using the entrances in the SgB in a round- robin fashion, the top brood chamber becomes a "bee generator" for the lower colony.
The top brood chamber, being queenless and initially containing all the eggs, larvae and brood will immediately commence to raise a new queen. However, the top brood chamber will not swarm because the population never reaches sufficient numbers to cast a swarm. The bottom chamber never swarms because the brood rearing cycle was interrupted by the initial manipulations.
This method artificially casts a swarm from a colony, keeps both populations in a single unit, effectively sets up a two queen colony, and leaves a requeened colony at the end of the season when the upper and lower chambers are reunited.
