The bees cannot be allowed to mingle or the queens will battle and one or both will end up dead. The idea of dividing a full sized box into two or more nucs is economy - for every full size box, you have two, three, four or even five nucs. The only additional equipment required is divider boards to completely isolate each compartment and a system of individual tops for each nuc. In cooler climates, the bees in adjacent compartments will cluster against the same divider board effectively improving cluster heating efficiency.